Australian Open most resembles U.S. Open among the Slams both in outcomes and in conditions of play. Over the past decade the best predictor of outcomes at Australian Open has been the previous year's U.S. Open. Both are played on hard courts, and both take place amid summer temperatures that are sometimes extreme.
 
Years ago a slow bounce prevailed at the Australian, thereby distinguishing that event from the faster conditions at the U.S. But the Melbourne courts were changed to reduce their grittiness and the associated ankle and leg injuries. In the men's singles last year (last four rounds), in a break from previous patterns, aces were more frequent at the Australian than at the U.S. Open. Thus the bounce on the Australian courts may now be as fast as on New York's.
 
THE BIG FIVE IN MEN'S TENNIS
 
The already classic Federer-Nadal rivalry has produced a Dual Monarchy atop the sport, where the two megastars have captured the top two places in the ATP rankings in every one of the last six years. Third and fourth places have also been stably occupied -- by Djokovic and Murray, in each of the last three years.
 
One or another of these four players has won every Slam but one since 2005. They provided the four finalists at last year's Australian and U.S. Opens. (Federer beat Murray in the final at Melbourne, Nadal beat Djokovic at the U.S.) Then at the ATP World Tournament in London late last year, they became the four semi-finalists who faced off to decide the crown.
 
The Big Four became the Big Five early this month, when Robin Soderling captured the tournament in Brisbane. The Swedish hammer thus passed Murray to become #4 in the rankings. Soderling and Murray should meet each other at Melbourne Park, as the two are drawn into the same quarter.
 
Rafael Nadal
 
At first glance Rafael Nadal seems the most likely winner at Melbourne. As champion at Garros, Wimbledon, and U.S. Open in 2010, Rafa, 24, has a chance to join the select group having won all four Slams consecutively. It would be his tenth Slam triumph, his second in Australia.
 
Almost unchallenged as perennial clay-court champion early in his career, Rafa then made major adjustments to improve on fast courts, developing a more forceful serve, staying closer to baseline in back-court rallies, and sometimes employing a severely sliced backhand. Now strong in any situation, he remains most dangerous in second-serve points, having led all pros last year in point-winning percentage when serving second serves and also when receiving second serves.
 
Rafa won Australian Open two years ago at age 22, during a stretch when Federer was weakened by illness. Then last year Federer recovered the crown, when it was Nadal who was not as his best. (Rafa fell behind Murray in the quarter-finals and then retired with a recurrence of knee trouble.) Now, Rafa seems at full health.
 
Roger Federer
 
At age 29, Roger gives away five years in youthfulness to the other members of the Four, and it is clear that his playing edge over the others has diminished. But he led all others in ATP hard-court ranking points in 2010, convincingly ahead of second-place Nadal in this indicator. He stands as a four-time champion at Melbourne and the current defending champion.
 
Roger lost narrowly at last summer's U.S. Open to Novak Djokovic in a fierce five-set semi, where Roger paced himself, conserving energy after falling behind in sets two and four. Whether Roger's age contributed to his loss of the fifth set remains only a suspicion. But it seems likely that Roger will be disadvantaged against younger players in the best-of-five-set competition and the sometimes-brutal heat at Melbourne.
 
Assuredly Federer remains close to his best ever. He obtained revenge over Djokovic at the ATP World in London, defeating the Serbian in two straight sets, and he began the ATP 2011 season by defeating Davydenko in the final round of the opening tournament at Doha.
 
Novak Djokovic
 
Novak Djokovic won his only Slam at Australian Open 2008. At age 23, height 6-3, Novak brings a potent serving and stroking style along with good variety, excellent court movement, and a determined court manner, all seemingly necessary attributes for membership among the Four. At his most brilliant when his opponent is serving, he ranks at or close to the top in point-winning and game-winning percentages when receiving. He has finished the last three years at #3 in the points ranking.
 
Novak's stamina has sometimes seemed questionable amid recurrent breathing problems, perhaps allergy related, but he has learned to manage this difficulty, for example in outlasting Federer in their U.S. Open epic last September. Carrying a large burden in Serbia's Davis Cup run during 2010, he succeeded brilliantly. That he is capable of winning again at Melbourne is unquestionable.
 
Andy Murray
 
Andy Murray, at age 23 and height 6-3, is similar to Djokovic in age and physical dimensions. Andy is capable of extremely potent and sustained artillery in serving and stroking, along with magnificent court mobility and defensive skills, comparable to and perhaps superior to Djokovic in both regards. Andy lagged behind Novak in past performances at Melbourne, but that changed with Andy's runner-up finish last year.
 
Murray and Djokovic did not meet in 2010. But Andy won their last three meetings before 2010, all on hard courts, all in straight sets. Both Murray and Djokovic won three matches without loss in the Hopman Cup competition in the first week of January 2011.
 
Murray's preference for relatively patient and defensive tactics perhaps hurts him against the other members of the Four. In sometimes showing a more attacking style of late, he has seemed to respond to such criticisms.
 
Robin Soderling
 
Robin Soderling, listed at 6-4 and 192 pounds, is assuredly a heavy hitter. He ranks third in total aces for 2010, behind Isner and Roddick. His devastating power off a roundhouse, flattish forehand, can create sequences of winners with little warning, and indeed by its very weight alone can force openings against even top players. Meanwhile the backhand is almost as potent. Robin's high serving toss can lose effectiveness in windy conditions, but indoors or in highly enclosed arenas, as are found at Melbourne Park, he is at his most effective. His career turned upward in early 2009, where at Garros 09 his rocketry terminated Nadal's extended run of clay-court success. Since then Robin has maintained his place among the elites.
 
THE PREDICTIONS
 
The chances thus seem slim, less than one in ten, that a player outside the Big Five will find his absolute best tennis and emerge as the forthcoming champion at Melbourne. Candidates for this role include an again-healthy del Potro, a recently surging Davydenko, a still-improving Gael Monfils, or perhaps an extreme server and stroker like Berdych or Roddick.
 
The predictions that follow rely on the following:
 
--Calculation 1, where results of the last thirteen months are weighted according to how well each tournament previously predicted results at Australian Open, and
 
--Calculation 2, where head-to-head results are weighted according to margin, recency, and commonality of playing surface.
 
Where the two Calculations disagree as to the probable winner of a match-up, the one showing the stronger margin of difference prevails. The method correctly pointed to the men's winner in three of the four Slams of 2009.
 
TOP QUARTER
 
The draw seems favorable for Rafael Nadal, but several dangerous possible opponents lurk. In the fourth round, Rafa is likely to meet Marin Cilic, who beat Rafa in their only meeting to date, at Beijing in 2009. But Marin's upward rise became halted at about that time, and he finished 2010 at the same #14 position that he held the year before -- hardly auspicious for a player barely in his twenties.
 
The lower half of the quarter harbors David Ferrer, a determined member of the Armada who can bring out Rafa's best but who has lost all five of their meetings in the two-year window captured in our Calculation 2. Perhaps more dangerous for Rafa would be David Nalbandian, whose play in the second half of 2010 after recovering from leg trouble and hip surgery in 2009 has been strong. Michael Youzhny lacks the weaponry and mobility to overturn Rafa.
 
--Ferrer over Nalbandian. Ferrer's moderate margin in 13-month performance (Calculation 1) is reduced by Nalbandian's win at Canada 2010. The two were scheduled to meet in the final at Auckland prior to the start at Melbourne.
 
--Youzhny over Ferrer. Calculations 1 and 2 disagree. Youzhny's two head-to-head wins in 2010 outweigh David's small edge in Calculation 1.
 
--Nadal over Cilic
 
--Nadal over Youzhny. Rafa is comfortably ahead in both Calculations.
 
SECOND QUARTER
 
Soderling and Murray are the giants here. Their quarter-final meeting could be magnificent.
 
--Soderling over Tsonga. Robin ahead in both Calculations.
 
--Melzer over Baghdatis. The two have never met, so the narrow edge by Calculation 1 goes to the Austrian player.
 
--Murray over Melzer. Andy has never lost in their five meetings.
 
--Murray over Soderling. Murray defeated Soderling in first-day action at ATP World 2010 in London, and Soderling beat Murray at Indian Wells 2010. Both affairs were straight-setters, where the former, being more recent, carries slightly heavier weight than the latter by our formula. Murray thus leads in Calculation 2, supporting his narrow lead in Calculation 1.
 
THIRD QUARTER
 
This is the quarter of Djokovic, who should advance comfortably through four rounds. He will then meet the survivor of the three elites in the quarter's other half -- (1) strong and athletic, big-serving Tomas Berdych, (2) dangerous Nikolay Davydenko, whose return from damaged wrist has been impressive and who defeated Nadal at Doha early this month, and (3) Fernando Verdasco, a strong-serving lefty just outside the top eight.
 
--Verdasco over Davydenko. With Davydenko then healthy and at his best, Nikolay won their five-setter at Australian Open 2010. Nikolay's head-to-head edge also prevailed in their earlier history. But the Spanish player's margin in Calculation 1 is stronger still.
 
--Berdych over Verdasco. Both Calculations point to Berdych, albeit closely. Berdych won their two hard-court meetings in 2010.
 
--Djokovic over Berdych. With the clear edge in 13-month performance (Calculation 1), Novak also won three of four head-to-head meetings in 2009-2010 and four of five lifetime.
 
BOTTOM QUARTER
 
The upper half of this quarter should bring together Roddick and Monfils for one of the tournament's closest match-ups. Meanwhile Sir Roger is unchallenged in the lower half.
 
--Roddick over Monfils. The French star has won their last two meetings, including at Tokyo in late 2010, and leads in Calculation 2. But the relentless weight of Andy's serving, stroking, and determination, seen in his superior score in Calculation 1, is narrowly enough to overcome Gael's flair and athleticism.
 
--Federer over Roddick. Roger leads in head-to-head play, 5-0 in last two years, 20-2 lifetime.
 
FINAL FOUR
 
Andy Murray's win over a hobbled Nadal one year ago in Melbourne swings Calculation 2 to Andy's favor even though Rafa won four of their seven meetings in the calculation's two-year window. But the likelihood that Murray can now sustain the level of performance and concentration needed to prevail for three sets against a healthy Rafa seems faint. Rafa's strong edge in Calculation 1 confirms this belief. Nadal over Murray.
 
Roger Federer faced Novak Djokovic ten times in 2009-2010. Roger won six times, including all three meetings subsequent to Novak's win at U.S. Open. None of the three were best-of-five setters, however, so Roger's ability to sustain his best against a superstar nearly six years younger remains at issue. Every point will sizzle, and the verdict may depend on the air temperature. Federer over Djokovic.
 
Another chapter in the Federer-Nadal saga thus seems ahead. They played each other only twice during the 2010 tour and only twice in 2009, each man winning once in both years. Rafa leads in their career-long tally of wins, 14-8. Only once have they met in best-of-five set competition on a hard court, when Rafa won their five-setter at Australian Open 09.
 
The two rivals, friends, played two charity exhibitions in late December 2010, each man winning in his home country. Rafa then won the six-player non-ATP event on a hard court in Abu Dhabi during the New Year's weekend. (Nadal beat Berdych in the semis, and Federer beat Soderling to reach the final.) Late in the first set Rafa found his top game, relentlessly ripping back Roger's best thrusts while playing moderately forcing, yet error-free tennis. Seemingly desperate to win points, Roger uncharacteristically slipped into high-risk tennis, firing extreme sizzlers to the corners early in points. Some of Roger's rockets were spectacular winners. But the errors came too regularly to alter the outcome, which went to Rafa by score 76 76.
 
Nadal leads comfortably in our Calculation 1, his three Slam triumphs last year outweighing Federer's victories in Australia and in London. Meanwhile although the head-to-head difference is small, Rafa also leads in Calculation 2.
 
Rafael Nadal is thus our predicted winner, where our calculations reinforce the evidence from Abu Dhabi and the hint that the nearly five-year age difference could be deciding. Assuredly we can expect to see plenty of fireworks in their newest clash, with momentum shifting several times. Neither man dare relax momentarily, as both know the likely fate of an offering too soft. Both know that winning a set requires playing hard from its outset and throughout.
 
WOMEN'S SINGLES
 
Serena Williams, now 29, has won Australian Open five times, including in both 2009 and 2010. But because of a troublesome foot injury that happened after last year's Wimbledon, Serena will miss Australian Open 2011. There is no shortage of strong candidates to claim her crown.
 
Here, we explore six indicators, each offering clues to probable outcomes at Melbourne Park:
 
1. The 2010 WTA point standings
2. Hard-court performance in 2010, a subset of the first indicator
3. Success at past Australian Opens
4. Wins over elite players minus total losses, 2010
5. W-L perfomance in tune-up events of early 2011
6. Pattern of improvement
 
Besides Serena, also absent from the Open will be perennial contender, Elena Dementieva, who recently retired. Both are removed from the lists that follow:
 
1. Overall performance -- WTA point standings for 2010
 
Leaving out Serena, here were the leaders in the 2010 standings. They are the top-seeded players in the four quarters of the draw at Melbourne Park.
 
1. Caroline Wozniacki, 8,035 WTA ranking points in 2010
2. Vera Zvonareva, 6,785
3. Kim Clijsters, 6,635
4. Venus Williams, 4,985
 
The leader, Caroline Wozniacki, now 20, rose from the pack after Serena's departure in the second half of 2010. She finished the year as the #1 player in the standings, even though she did not win or indeed reach the final of a 2010 Slam. Although she competed well in the year-ending WTA World championship in Doha, she was clearly outstroked by Kim Clijsters in their three-set title-round match.
 
Second in this indicator is Vera Zvonareva, 26, the runner-up at both U.S. Open and Wimbledon 2010. Vera showed her ability to stand up to the other leaders in head-to-head play during the year. Meanwhile Kim Clijsters, 27, third here, was troubled during 2010 with injuries to the right foot and then the left foot. She played in only twelve tournaments, but she won four important ones -- Miami, Cincinnati, U.S. Open, and Doha. Well behind in fourth place, is Venus Williams, now 30, who played in only nine events in 2010 because of knee trouble. Venus lost to Clijsters in a three set semi at U.S. Open and also lost to Kim at Miami.
 
2. Hard-court performance
 
Our tally of 2010 hard-court results (outdoors and indoors), is shown here:
 
1. Caroline Wozniacki, 6,448 points
2. Kim Clijsters, 5,985
3. Vera Zvonareva, 4,883
4. Victoria Azarenka, 3,544
 
Kim Clijsters's four tournament victories were all on outdoor hard courts. Another gainer here is hard-hitting Azarenka, whose triumphs at Stanford and Moscow and her two match wins in the round-robin phase at Doha all came on hard courts.
 
3. Past Australian Opens
 
Some tournaments seem especially suited to the strengths of certain players. This indicator therefore examines past performances at Melbourne Park. A player here receives one credit for each match won in a given Open plus one additional credit if she becomes the champion. Our score averages each player's best year at Melbourne with the average of her best five years.
 
1. Justine Henin, score 6.9 (best: 8, 5-yr avg: 5.8)
2. Maria Sharapova, score 6.6 (best: 8, avg: 5.2)
3. (tie) Venus Williams, score 5.3 (best: 6, avg: 4.6)
3. (tie) Kim Clijsters, score 5.3 (best: 6, avg 4.6)
 
Neither Henin nor Sharapova, the leaders in this indicator, are high in our first two indicators. Henin, who won the tournament in 2004, was runner-up for the second time last year. Venus and Clijsters, tied in third place here, both reached the final round at Melbourne one time. Other players who scored well in this measurement are Safina and Ivanovic, followed by Zvonareva and Petrova.
 
4. Elite wins minus total losses, 2010
 
This indicator has proven very helpful in past analyses. "Elite wins" here are wins over members of the year's top ten and also over past Australian champions Henin and Sharapova.
 
The verdict here is striking, where the clearly superior score is that of Clijsters. The only "elite" player to defeat Clijsters during the year was Zvonareva.
 
1. Kim Clijsters, 14 - 7 = plus 7
2. (tie) Venus Williams, 6 - 7 = minus 1
2. (tie) Justine Henin, 7 - 8 = minus 1
4. Caroline Wozniacki, 11 - 17 = minus 6
5. Vera Zvonareva, 10 - 18 = minus 8
 
5. Tune-up events of 2011
 
Here are the top performers in the tune-up weeks for the Australian (Hopman Cup, Brisbane, Auckland, and Hong Kong in the first week of January, Sydney and Hobart in the second week, where Hobart is still in progress). A player's score is her wins minus losses plus one credit if she wins the tournament.
 
The four leaders as of the date of the Melbourne draw are the respective winners at Brisbane, Auckland, and Sydney (Arn, Kvitova, Li), along with Bethanie Mattek-Sands, who earned two credits at Hopman Cup and four more by reaching the final at Hobart. Just behind is Henin, who defeated four opponents in winning Hopman Cup. Vera Zvonareva defeated two opponents, including Wozniacki, in winning at Hong Kong., but she then lost her first match at Sydney. Kim Clijsters skipped the first week but then won four of five at Sydney.
 
1. (tie) Greta Arn, 6 credits
1. (tie) Petra Kvitova, 6
1. (tie) Li Na, 6
1. (tie) Bethanie Mattek-Sands, 6
 
6. Pattern of improvement
 
Here we measure each player's recent pattern of improvement, taken from the WTA year's rankings of the last four years.
 
Scoring highest is Caroline Wozniacki, whose pattern of rise, measured exponentially, seems close to classic for an emerging new champion. Her WTA final rankings in the four years starting in 2007 were #64, #12, #4, and #1, successively. Although Caroline cannot improve on her #1 ranking of 2010, the numbers here strongly suggest that her playing ability has not yet peaked.
 
1. Caroline Wozniacki, #64, 12, 4, 1 = score 267
2. Sam Stosur, #47, 52, 13, 6 = score 135
3. Alexandra Dulgheru, #249, 385, 51, 29 = score 124
4. Vera Zvonareva, #23, 7, 9, 2 = score 83
 
ASSEMBLING THE INDICATORS
 
The message of our indicators seems clear. There are two outstanding favorites. One of them is young, has risen rapidly, and seems ready to continue improving. That is Caroline Wozniacki, who leads in three of the indicators. The other is a several-time Slam winner, a former runner-up in Australia, who returned from retirement in mid-2008. That is Kim Clijsters, who is near the top in four of our indicators. Kim strongly leads in the one that seems to me the most telling -- elite wins over losses.
 
Here, we assemble the indicators, weighting all six of them equally. (Each indicator is normalized to a total of 1,000 points, apportioned among its top sixteen finishers.)

1. Wozniacki, assembled score 770 points
2. Clijsters, 673
3. Zvonareva, 516
4. Henin, 400
5. V. Williams, 337
6. Stosur, 297
7. Schiavone, 231
8. Li, 214
9. Azarenka, 187
10. Sharapova, 137