Once again the tennis world looks to Australia. Some pro warriors spent their recent break from tour action for physical and mental renewal. Others used the time for intensive training, or perhaps made on-court appearances away from the main-tour grind. The off-season also produced an interesting first-time team venture -- the International Premier Tennis League, staged in four cities in Asia and featuring several top-level stars male and female.
 
With the January tune-ups now nearly complete and the tournament's qualifying rounds well underway, Australian Open 2015 brings together the world's best players, competing at probably the highest-ever level of skill and athleticism. Last year, the Open produced two first-time winners of the event. Novak Djokovic had been the men's champion the last three years, but he now lost to Stan Wawrinka in a fabulous five-set quarter-final. Then in the final round Wawrinka fought past Rafael Nadal, whose back trouble hampered his power and precision mid-way. It was only the second of the last 35 male Slams not won by one of the sport's long-standing Big Four. Meanwhile Li Na became the first player from China, male or female, to triumph at the Open. Tournament favorite Serena Williams lost in the third round to Ivanovic, and the winner the last two years, Victoria Azarenka, lost in the quarters to Radwanska.
 
Wawrinka but not Li would remain near the top. Stan's ranking would stabilize at #3, then slip to #4 after Wimbledon. At year's end it was Stan finishing in the glory of Switzerland's Davis Cup triumph. Meanwhile Li Na attained moderate success at Indian Wells and Miami, but later in the year, plagued by damaged right knee, Na at age 32 announced her retirement from pro tennis.
 
MELBOURNE PARK
 
Spells of summertime temperatures can be expected during the Open. Last year, extreme heat marred the first week, bringing a record number of first-round retirements by players. The rules allow for suspension of play under prescribed conditions (where play is stopped upon completion of any set in progress).
 
For the first time at any Slam, there will be three arenas having retractable roofs and air conditioning. Laver Arena (seating 16,000) and Hisense Arena (seats 10,000) have been covered for several years. Newly roofed is Margaret Court Arena (upgraded to 7,300 seating). Officials calculate that if necessary the full tournament schedule could be played indoors.
 
The hard courts at Melbourne Park produce bounce speeds similar to those at U.S. Open and intermediate between speeds on Wimbledon grass and Garros clay.
 
Australian Open also tends to produce the most predictable match outcomes. (Wimbledon the least predictable.) Here, for example, is the average number of male players annually intruding into the tournament's final sixteen who were not originally seeded to reach that level, 2001-2014:
 
-- Australian Open, 6.07
-- U.S. Open, 6.57
-- Garros, 7.00
-- Wimbledon, 8.21
 
The above numbers seem to correlate with the irregularities of the respective court surfaces.
 
In next evaluating the principal candidates at the Open and their chances for winning, we rely heavily on four numerical Indicators. The Indicators are summarized in the footnote at the end of this column.
 
MEN'S SINGLES 2015 -- TWO PRIMES
 
Novak Djokovic, age 27, height 6-2.
 
Novak Djokovic, 27, is now amid what are probably the peak years of his career. He has already triumphed at Melbourne Park four times. In achieving his #1 rank for tennis-year 2014 he won Wimbledon, won four of the nine Masters Series tournaments, and captured the year-end finale in London.
 
Tall, athletic, and physically flexible, Novak is close to the world's best in every department of the game, favored by his remarkable mobility and body control. He generally plays patiently, using his movement and accuracy to sustain moderate pressure on an opponent in extended rallies. He is almost always better than his opponent in winning long, physical exchanges. But he is also capable of forceful, attacking play, including especially in serve-returning, where his points-winning percentage when returning second serve was best on the pro tour in 2014, well ahead of second-place Nadal.
 
Our indicators confirm Novak's preeminent chances at Australian Open 2015. He is ahead of all others in Basic Indicator. Djokovic is also first in Quality-Win Quotient, QWQ, which measures recent success against top-level opponents. He also leads in Composite, which combines the other four indicators.
 
Since his season-ending triumph in London, Novak has remained active and apparently free of injury, though successes have been few. He played several one-set singles matches in International Premier Tennis League, defeating Monfils and losing closely to Tsonga, Federer, and Berdych. At Abu Dhabi, 1-3 January, he defeated Wawrinka but then withdrew prior to the final match against Andy Murray because of illness. He won twice at the Doha tournament before losing to big-serving Karlovic in three sets.
 
Roger Federer, 33, 6-1.
 
Roger did not win a Slam in 2014, but he re-established himself as a strong threat to do so in the future amid many magnificent performances against top tier opponents. He was runner-up to Djokovic at Wimbledon, where he lost in a superb five-setter, and withdrew prior to his final-round match with Djokovic at the year-end finale in London, seemingly to improve his chances in the Davis Cup final the next week. Roger finished at world rank #2, improved from #6 at the end of 2013. He ranked first in our indicator Hard-Court Index, HCX, measuring 2014 performance on hard courts. Roger's score in Composite was thus a close second to Djokovic's.
 
Roger's resurrection in 2014 owed much to his aggressive style of play which became more evident as his earlier back trouble improved. Roger, who turned 33 during the year, knew that his foremost opponents, all six years or so younger and capable of mobility and firepower roughly equal to Roger's, could not be beaten by patience. Roger's main superiority lay (1) in his net skills and (2) in the quality of his attacking weapons that enabled him to move forward.
 
Thus against opponents of the top tier during 2014, Roger almost always played highly aggressively. His forceful serving was important, often producing aces or missed returns by opponent or, equally important, obtaining serve returns that Roger could attack. Thus seizing the initiative, Roger might end matters behind his first strike or perhaps with further heavy artillery to the corners or sides, ready to advance as soon as feasible.
 
It can therefore be confidently predicted that Roger will be the more aggressive player against any top opponent at the Open. Sometimes he may conserve energy to improve his ultimate winning chance. But when he wants his best -- whether he is ahead in a set and serving, or during tiebreak games -- he knows that he must attack early, even in situations that might be too risky for most others.
 
Federer and Djokovic played five times in calendar 2014 (not counting Novak's walkover win in the year-ender). Roger won three times, Novak twice. There was one other meeting, a one-setter, when Roger, playing for the Indian team in New Delhi on 8 December, defeated Djokovic, playing for Dubai (U.A.E.). The event thrilled the crowd of reportedly 16,000 as well as the league's principal organizer, former doubles star Mahesh Bhupathi, who deemed their set "of a quality that has never been seen in my country before."
 
On Turning 34 -- Bill Tilden and Federer
 
With his prime years now behind, how well can Federer maintain his championship-level ability, especially in Slams where matches are best-of-five sets? Perhaps clues lie in the long-ago career of the great Bill Tilden.
 
Like Roger, Tilden dominated big-time tennis while in his twenties and early thirties. Tilden's zenith seemed past in 1927, the year when he turned age 34 (as will Federer in 2015). That year saw Bill beaten at Garros, Wimbledon, and U.S. Nationals by French stars Rene Lacoste and Henri Cochet, and also in the Davis Cup final. The latter loss ended the U.S.'s seven-year run as Cup champion nation. In those seven years of triumph, Tilden had won 13 of his 14 Cup challenge-round singles plus 3 of his 4 doubles appearances.
 
But if most of Tilden's glory came prior to 1927, Bill's playing level would remain amazingly high long after that year. There would be one more triumph at the U.S. Nationals (Bill's seventh, in 1929) and one more at Wimbledon (his third, in 1930). Tilden would lead the U.S. team at the Davis Cup challenge round in all three years 1928-1930, all played on clay at the new stadium at Roland Garros, all won by the Musketeers despite one singles victory in each case by Tilden.
 
Tilden then turned pro in 1931 at age 37, ending his Slam and Davis Cup play. At first he regularly defeated all comers among the world's professionals. Reflecting observations from pro-tennis watchers at the time, one writer (myself) deemed that Tilden's playing ability became stronger amid his almost daily matches against other leading pros, probably exceeding his best in his late amateur years. Unlike in amateur tennis where many matches came in the early rounds of tournaments against much weaker opponents, on the pro tour Tilden's daily opponents were always near-equals.
 
Bill would comfortably handle Cochet upon the arrival among the pros of Henri in 1933. Bill would be then be challenged as king of the pros by rising German pro Hans Nusslein, and both would be superseded upon the arrival of Ellsworth Vines in 1934. Even so, Bill at age 40 would defeat Vines -- the recent Wimbledon and twice U.S. champion, who was just 22 in age -- in their Madison Square Garden opener. Vines would win the ensuing transcontinental tour with Tilden by margin of just two matches.
 
Tilden and Nusslein would remain Vines's most dangerous opponents until the 1937 arrival of Fred Perry, three-time consecutive Wimbledon champion. (Perry and Vines would each win 35 matches in their long tour of America and a short sequence in the British Isles in 1937.) Tilden, now 44, could still be competitive, defeating Perry in three of their seven meetings in 1937. Perry wrote that Tilden's greater variety and unpredictability made him a more difficult opponent than Vines in these areas. My ranking of Tilden as World #8 among all pros and amateurs for 1937 is readily defended and may be too cautious. (I placed Tilden behind pros Perry, Vines, and Nusslein, and amateurs Budge, German players von Cramm and Henkel, and Britisher Austin.) Ruined by disclosures of his moral deviancy and imprisonments, Tilden occasionally competed in pro tennis events until his death in 1953.
 
But as a relentless tennis warrior, Tilden had remained among the world's best players -- i.e., within the top eight -- until reaching the age of 44 in 1937. Could Federer perhaps do the same over the next ten years?
 
It is hard to believe that Roger will decide to try. Big-time tennis has grown vastly since the times of Tilden. The stars and superstars are far more powerful, are drawn from a much larger population of aspirants, and are subjected to rigors of preparation and training much beyond that known long ago. The physical demands for rising to the top and staying there are immeasurably greater.
 
Roger of course had benefit of more-advanced scientific knowledge in medicine, therapy, and training, and assuredly took better care of his health. In both cases, Roger's and Bill's considerable level of superiority over most opponents during their twenties allowed both champions to stay on top amid minimal wear on their athletic frames.
 
Our answer will lie in Roger's future health and willingness to forfeit a reasonably normal life. It seems unlikely that he will subject himself and his family to a commitment of active competition anything like Tilden's after age 34.
 
But Tilden's amazing performance up to age 44 suggests that if Roger decides to make the sacrifices, his playing career is now far from over.
 
THE OTHER PRIMES
 
Our indicators clearly make Djokovic and Federer the top favorites for success at Melbourne Park. They are the twosome most likely to meet in the final. But the probabilities argue that at least one of them will fail to reach that goal. The second and third tiers, next sketched, offer an abundance of talented and strong-willed candidates.
 
Rafael Nadal, 28, 6-1.
 
After winning his ninth Garros crown in ten years and thereby maintaining his world #1 rank, Rafa experienced a difficult second half of 2014 -- a nagging wrist injury, talk of a new approach for overcoming to his back problem, and then a late-year bout with appendicitis. He returned from appendix surgery in January 2015 at Abu Dhabi, losing to Murray, then defeating Wawrinka for third place.
 
Rafa has always been at his most dominating on clay, having collected his first four Slams on Garros clay. But at mid-career he enlarged his weaponry, beefing up his serve and developing a more aggressive playing style. He still possessed superior court mobility and his singularly extreme topspin in his ground-strokes, but he became comfortable in taking aggressive position close to baseline during exchanges, striking with full velocity to the corners earlier in points. His forehand thunderbolts became often point-enders, and his backhand two-handers sometimes equally so. His explosive offensive ability, generally from back court, joined to his defensive trademark, have produced five Slam triumphs on nonclay surfaces to go with his current nine Slams at Garros,
 
If Rafa has regained his full health and ability, he would join our two favorites, above, in his chances at Melbourne. Last year he defeated Federer there in straight sets before losing in the final round to Wawrinka in four. Rafa was also runner-up at Melbourne Park in 2012 and was champion there in 2009.
 
Stan Wawinka, 29, 6-0.
 
When Wawrinka is at his powerful best, as when he captured AusOpen 2014 and again in several performances late in the year, Stan is capable of defeating anyone. His potent serve and ground strokes, especially his backhand one-hander, can preempt the better mobility and variety of the game's most accomplished superstars. (In 2014 Stan defeated Djokovic in Melbourne, and he defeated Federer at Monte Carlo on clay, took a set in losing to Roger at Wimbledon on grass, and very nearly beat Roger at the year-ender in London, losing in three brutal sets that led to Roger's withdrawal prior to the final the next day.)
 
Stan stood at world rank #4 at the end of 2014, and he cemented a first-four seeding at Melbourne Park by strong results in early January, again winning the tune-up at Chennai.
 
Kei Nishikori, 25,5-10.
 
The remarkable rise of Kei Nishikori during 2014 -- from world rank #17 at the starrt to #5 at year's end -- commanded wide attention. With a firm and well-rounded game built on excellent court mobility and clean ball-striking, Kei during 2014 captured four tournaments amid an overall W-L record of 54-14. His spectacular run to the finals at U.S. Open 2014 included wins in five sets over Raonic and Wawrinka and in four sets over Djokovic. He then finished the year strongly, capturing Kuala Lumpur and Tokyo and scoring wins over Murray and Ferrer (balancing losses to Federer and Djokovic) at the London year-ender.
 
Kei's is a superbly tailored baseline game, built upon superb movement and clean, accurate striking. Confirming his readiness was his close loss to Raonic in Brisbane (in three tiebreak sets) to start the new year.
 
Andy Murray, 27, 6-3.
 
Held back in recovering from 2013 back surgery, Andy Murray dropped out of the top four in the rankings in 2014 for the first time since 2011, finishing the year at #6. But he stood #3 in his results during the third trimester, when he scored triumphs at Shenzhen, Vienna, and Valencia and quarter-final finishes at U.S. Open, Cincinnati, and Canada, all on hard courts.
 
Andy has excellent easy power in striking, where the ball seems to rocket off his racket with relatively little effort by himself. His preference for defensive play, however, violates the current trends in top-level tennis, which favor aggressiveness both in striking and court position. His resolve to play more aggressively seems easily discouraged when it is most needed -- i.e., against the other topmost players.
 
He lost all four matches to Djokovic during 2014, winning only one of their ten sets. But he surged well in the off-season, winning the event at Abu Dhabi.
 
OTHER THREATS
 
Milos Raonic, 24, 6-5. Strong results in the second and third trimesters of 2014 were followed in January at Brisbane by his win over Nishikori and close loss to Federer. His serving prowess is unmatched among the superstars, he having finished in second place behind Karlovic in total aces 2014.
 
Grigor Dimitrov, 23, 6-2. Youngest member of the upper tiers, he has competed closely against the established top group.
 
David Ferrer, 32, 5-9. Has been just outside the Big Four since that elite group became recognized.
 
Tomas Berdych, 29, 6-5. Has shown the easy power and court prowess to break out upward but only rarely has threatened to do so.
 
Juan Martin del Potro, 26, 6-6. Returning from a long absence for a second wrist surgery. He won two matches at Sydney in January but lost in the quarters in two tiebreak sets.
 
Note that neither Jo-Wilfried Tsonga or Marin Cilic will compete at Melbourne Park because of injury problems.
 
MEN'S DRAW AND PREDICTIONS
 
Top Quarter. The quarter seems surely Djokovic's. Milos Raonic is his likely opponent in the tournament quarter-finals though getting there will be dangerous for Milos in a field including Monfils, Janowicz, and del Potro. The latter two sluggers, both unseeded, must face one another in round one. Djokovic is the choice over Raonic given Novak's talent in returning strong serves, his past four wins against Milos without loss, and his strong edge in our indicators.
 
Second Quarter. Stan Wawrinka is seeded atop the quarter, and Stan should march unchecked to the quarter-finals. But Kei Nishikori lurks in the lower half of the quarter where Kei's main rival, David Ferrer, cannot match Kei in sustaining forceful pressure during exchanges. Kei defeated David in all four of their meetings in 2014, though all four were split-setters, and he is ahead in all indicators including Riser, where he scores points in ninth place to increase his lead in Composite. Nishikori also leads Wawrinka in all indicators except Basic, where the margin is small. Kei defeated Stan in a five-setter at U.S. Open 2014 in their only meeting since 2012. Our choice is Nishikori.
 
Third Quarter. This is the realm of Rafael Nadal, who has beaten his likely quarter-final opponent, Tomas Berdych, in their last 17 meetings reaching back to 2007. If he is physically right, Rafa's weaponry should comfortably prevail.
 
Bottom Quarter. Roger Federer's path to the final four is less secure. Roger's likely opponent in the third round is Ivo Karlovic, who has often extended Roger to extra sets and who has been playing well lately, having defeated Djokovic at Doha in early January. Roger's opponent in the quarter-final will be either Andy Murray or Grigor Dimitrov. Andy leads Grigor in all indicators except Riser where Grigor, being four years the younger, scores as more likely to show further improvement. Murray is the choice over Grigor here in heed of his clear edge on hard courts including a straight-set win over Dimitrov at Paris Indoors in 2014. Thus Federer and Murray should meet in the final of the quarter. Roger in 2014 won all three of their meetings, all on hard courts, thereby reversing Murray's remarkable previous career edge in facing Roger.
 
Semi-final, Djokovic vs. Nishikori. These two are not far apart. Nishikori beat Djokovic at U.S. Open 2014 but then lost indoors in Paris and London. Novak leads in our indicators, but the Japanese riser has shown increasing ability to maintain high level in long matches. Nishikori, however, surprisingly lost to Gasquet at Kooyong this week in two tiebreak sets. Djokovic, who usually brings his best tennis to Australia, should prevail.
 
Semi-final, Federer vs. Nadal. Rafa has won their last five meetings, including at Melbourne Park last year. Roger leads in all our indicators, which largely reflect performance in 2014 when Roger was the healthier of the two. It probably comes down to physical health -- which player is strongest on the date of their semi. Nadal, whose path to the final four was the less demanding, could have the edge. But Roger, who seems less challenged by recent injury problems and has shown top form regularly in recent months, is our choice.
 
Final, Djokovic vs. Federer. Roger has the small edge in head-to-head play. Djokovic an almost-as-small edge in our indicators except for Roger's primacy in Hard-Court Index. It is hard to imagine that Roger could advance through the tests of the earlier rounds without considerable weakening of physical reserves. Novak has the ability to limit Roger's edge in serving and net play. Novak won their last two meetings at Australian Open. Their meeting in the final round of 2015 should see Djokovic at the winner's circle to claim his fifth Australian Open crown.
 
WOMEN'S SINGLES -- THE ONE AND ONLY
 
Serena Williams
 
Twelve Slams were played during the years 2012-2014. Serena won five of them. She also won all three of the year-ending finales during the period along with seven of the twelve Premier Mandatory tournaments as well as Olympic Games 2012. No other player came close to this level of success. Serena achieved all this after turning age 30 in 2011 while rarely free from concerns of sickness or injury.
 
Serena's superior serving ability most explains her late-career achievements. She regularly led the women's tour in percentage of serving games won, increasing her winning percentage to well over 80 percent of late. Her serving velocities, placement, and disguise produced tour-leading totals of aces along with weak serve-returns from her opponents -- key to Serena's potent first-strikes and further attacks.
 
Complementing her serving is Serena's superb athletic mobility and stroking power, which together often neutralize and reverse an opponent's dominance during points. When her timing and rhythm are right, her bolts consistently find their targets and she becomes relentless in seizing command. And if an unusually strong opponent is able to withstand or neutralize the bombardment from back court, Serena often becomes willing to force her way forward to finish matters at net.
 
But surprisingly often of late, Serena has been unable to find the court with her own blistering strikes. Sometimes on these occasions she plays more patiently in expectation that her timing will return, maintaining just enough forcefulness to prevent opponent from taking up the attack. Often her timing returns in time for her return to aggressive play. Helping her reverse matters is the relentless effect of her renowned will and determination, underscoring her many retrievals of victory.
 
But there are also occasions when she seems tired, almost disinterested, lamenting her dismal play but without showing her well-known competitive fire. Inexplicable losses can happen.
 
Upon conclusion of tennis year 2014, Serena made appearances in World Team Tennis League, winning all four of her one-set matches. In January, she played Hopman Cup, coming from behind to defeat Pennetta, showing spells of top form. But next came one of those torpid occasions when Serena proved unable to find the energy to turn around a losing effort, against Bouchard. Serena afterwards complained of tiredness, jet lag, an inability to react to Eugenie's blows. Then came a close win over Safarova, she lost on the final day to Radwanska in Poland's triumph over the U.S. duo, Serena and John Isner. Her readiness now to summon her big game at Melbourne Park remained unproven.
 
Others
 
All others at Melbourne are clearly beatable for a Serena at her best. Of Serena's most dangerous recent challengers, most lack the extreme firepower and athleticism needed to out-hammer Serena. Even big-hitting opponents like Sharapova, Ivanovic, and Kvitova have fared dismally in their past head-to-head meetings with Serena. Older sister Venus Williams has the necessary weapons and has fared better in match-ups against Serena, but age and illness argue against Venus's current chances. Victoria Azarenka -- powerful, talented, at age just 25 and height 6-0 -- is a former world #1, having won Australian Open crown in both 2012 and 2013 and been runner-up to Serena at U.S. Open 2013. But her results faltered badly amid foot and other injuries through 2014, and her struggles to regain top form continued in a first-round close loss at Brisbane 2015.
 
A younger tennis generation probably will provide the superstar that will eventually unseat Serena. Simona Halep, 23, crushed an unready Serena at the Singapore round-robin at year's-end 2014, but Serena reversed that outcome decisively in the event's final match. Simona won the January tune-up at Shenzhen but then withdrew from Sydney with illness. Eugenie Bouchard, 20, whose results became disappointing after amazing showings in the first three Slams of 2014, recovered her fine attacking game against a below-form Serena at Hopman Cup 2015, noted above. Caroline Wozniacki, 24, once a prodigy at world #1, now shows a mature and more powerful playing style. Wozniacki was runner-up to Serena at U.S. Open 2014 and nearly defeated her in the semis of the Singapore year-ender. Top-seeded at Auckland in January, Caroline lost in a heavy-hitting three-setter to Venus Williams, and she then missed the next week's tournament at Sydney with wrist trouble.
 
Among the youthful newcomers showing well in early-January action were Taylor Townsend, 18, and Elina Svitolina, 20 (at Brisbane), Zarina Diyas, 21, and Tereza Smitkova, 20 (at Shenzhen), Lauren Davis, 21 (at Auckland), and Garbine Muguruza, 21 (at Sydney). All rank in the world's first hundred and all should be worth watching at Melbourne. Muguruza, Svitolina, and Diyas are seeded, as is highly regarded Belinda Bencic, 17, who lost her season-opener at Sydney, to Daria Gavrilova, 19, from Moscow.
 
DRAW AND PREDICTIONS
 
Top Quarter. It is not the easiest draw for Serena Williams. Newcomers Svitolina and Muguruza present interesting likely opponents in the early rounds, and Caroline Wozniacki lurks in the lower half of the quarter. Caroline stands third in our indicators, behind Serena and Sharapova. But her recent wrist trouble may affect her shot-making. Serena should advance.
 
Second Quarter. Venus Williams seemed at full health in winning at Auckland, so the tall American could, and indeed should, get by Agnieszka Radwanska to reach the final round of this quarter. Petra Kvitova, recent winner at Sydney, would be her next opponent. Left-handed and heavy-striking Kvitova, apparently healthy and near her best, should overcome a strong bid by Venus.
 
Third Quarter. The contrasting strengths of Simona Halep and Ana Ivanovic should provide a splendid final match to this quarter. During the first week of January Halep won the tournament at Shenzhen and Ivanovic was close runner-up to Sharapova at Brisbane. Ivanovic has slight edge in QWQ and HCX indicators, Halep in Basic. Our choice favors the heavier game of Ivanovic over the well-crafted skills of the younger star.
 
Bottom Quarter. There are some fine players in her path -- Diyas, Safarova, then either Kerber or Bouchard. But it is hard to see any of them stopping the relentless power of Mara Sharapova, whose triumph at Brisbane established her current high level. In the final match of the quarter, Sharapova over Bouchard.
 
Semi-Finals and Final. Despite her recent ups-and-downs, it is nevertheless likely that in the second week at Melbourne Serena will have found her big game. Her high mobility and athleticism should therefore carry her past Kvitova into the final. Meanwhile Maria Sharapova brings similar confidence. Ivanovic took their first set from Maria in the final at Brisbane, but Maria prevailed thereafter and should continue her dominance over Ana. Then in the final, Serena's pattern of success against Sharapova and her edge in our indicators should bring the crown to Serena. It will be her sixth triumph at Australian Open, her first since 2010.
 
THE TENNIS NATIONS
 
We measure our imaginary competition among the nations by awarding one credit for each main-draw singles win and one-half credit to the nation of each winning partner in doubles and mixed-doubles matches.
 
The nation leading in the tally of match wins among the men at Australian Open 2014 was France, lifted by a remarkable total of 12 wins in first-round singles. Spain was a close second, buoyed by Nadal's runner-up finish. Switzerland was third where both Wawrinka and Federer reached the final weekend. The choice this year is Spain, a prediction made likely by the absence of Tsonga from the French lineup and the recent physical troubles of ever-dangerous Monfils.
 
The U.S. women finished in first place last year despite the absence of Venus Williams. Russia, which had been first the previous ten years, was second. The probability of a strong contribution by both Venus and Serena this year and the likely improvement by a host of young American risers make the U.S. women our choice to prevail again.
 
Best wishes to all the stars, superstars, and aspirants, and those who follow and support them, for a best-ever celebration of the sport.
 
-- Ray Bowers, Arlington, Virginia, USA
 
FOOTNOTE: MORE ON THE INDICATORS
 
The top sixteen scores in each indicator are reduced by subtracting the value of the 17th-best score, and these values are then adjusted to reach a total of 100. Thus normalized, only the leading sixteen individuals in an indicator receive a score.
 
Basic Indicator
Each player's results in 21 predictor tournaments of 2014-2015 are weighted according to how well in the past each event has predicted actual results at ensuing Australian Opens. Most heavily weighted here are: U.S. Open 2014 at 9.15%, Wimbledon 2014 at 7.81%, Australian Open 2014 at 7.81%, Garros 2014 at 7.34%, and Indian Wells 2014 at 6.46%. Here are the leaders:
 
1. Novak Djokovic, score 20.05
2. Roger Federer, 16.11
3. Rafael Nadal, 10.52
 
Quality-Win Quotient, QWQ
Match wins in 2014-2015 against 13 quality opponents who are weighted in three tiers. Heaviest weight, threefold, is given for wins over Djokovic, Federer, and Nadal. Twofold weight is given for wins over Murray, Nishikori, Wawrinka, Raonic, and Berdych.
 
1. Novak Djokovic, 26.92
2. Roger Federer, 19.88
3. Rafael Nadal, 11.11
 
Hard-Court Index, HCX
Results on hard courts during 2014-2015 are tallied and weighted for recency.
 
1. Roger Federer, 20.09
2. Novak Djokovic, 14.86
3. Andy Murray, 10.28
 
Riser Index
Ratio of results in 2014-2015 weighted for recency vs. best previous 12-month ranking.
 
1. Alex Zverev, 14.25
2. Borna Coric, 14.41
3. Roberto Bautista-Agut, 12.25
 
Our women's indicators are calculated only slightly differently. Here are the leaders.
 
Basic: Serena Willliams 14.75, Maria Sharapova, 13.03, Agnieszka Radwanska, 12.41.
 
QWQ: Serena Williams 30.51, Maria Sharapova 19.23, Ana Ivanovic 11.54.
 
HCX: Serena Williams 18.94, Caroline Wozniacki 17.59, Ana Ivanovic 10.46.
 
Riser: Belinda Bencic 18.66, Karolina Pliskova 17.07, Zarina Diyas 14.10.
 
Composite: Serena Williams 14.75, Maria Sharapova 9.85, Caroline Wozniacki 7.57.