Ours has been a time of greatness in men's pro tennis, a new Golden Era perhaps, one that is still unfolding in the overlapping careers of Roger Federer and Rafael Nadal. Federer's winning of both Garros and Wimbledon in 2009 duplicated the same feat by Nadal in 2008 -- rare achievements both, of unquestioned historical significance. Roger at 28 has now captured 14 Slams over his career, the most-ever by anyone, and he is one of the few to have won every Slam at least once. He brings to U.S. Open 09 an unprecedented and still active run of five consecutive U.S. Open crowns. Meanwhile Rafael, who at 23 is five years younger than Roger, has won every Slam at least once except U.S. Open, a total of six in all -- more than Roger at the same age. When stopped at Garros 09 by Soderling and by his own bad knees, Rafael had achieved arguably history's greatest-ever run over a sequence of years at that crowning clay-court event.
 
Magnifying the appeal in their rivalry are the contrasts in their playing strengths. Nadal has been the relentless heavy hitter from back court who is the world's best defensive player and also a fine attacker. Meanwhile Federer has been the magnificent server with the absolutely superior forehand and attacking game, who is also superb defensively. Nadal has won 13 of their 20 head-to-head clashes to date, all but one in Master's Series or higher events. Roger won their most recent meeting, on clay in Madrid. Rafa won their only other meeting in 2009 -- their five-set final at Australian Open 09.
 
The Big Two -- Federer and Nadal -- became a Big Four in 2008 with the addition of two players who turned 21 during that year. Novak Djokovic won Australian Open, Indian Wells, and Italian Open in the year's first half, and Andy Murray won Madrid, Cincinnati, and was runner-up at U.S. Open in the second. Both have continued to show their ability to beat the top two in head-to-head meetings, Murray having won his last four against Federer prior to their meeting at Cincinnati last week. Djokovic won both his meetings with Federer in 2009 prior to Cincinnati.
 
Surging strongly this summer have been two players just outside the Big Four -- Andy Roddick, 26, and Juan Martin del Potro, 20. Roddick's rise included Wimbledon 09, where he beat Murray in the semis and narrowly lost to Federer in an extended-fifth-set final. In August 09, in the absence of the Big Four, Roddick and del Potro both reached the final in Washington, del Potro winning closely. One week later in Montreal, where the Big Four joined the cast, Roddick beat Djokovic and del Potro beat Nadal in the quarters, Juan Martin again beat Andy in the semis, and Murray beat a tired del Potro in a split-set final. These results seemed to confirm that the Big Four had indeed become a Big Six.
 
At the summer's concluding Master's Series event in Cincinnati the next week, the original Four attained the semis. (Roddick and del Potro did not compete.) Federer then defeated Murray behind determined attacking, while Djokovic defeated Nadal, impressively. Federer then claimed the crown by beating Djokovic strongly.
 
The dominance of the Six during August is especially notable given the impressive tier of stars just behind, most of whom have been playing well, all capable of forcing any of the Six to their best tennis. These include Tsonga (who beat Federer in Montreal), Verdasco, Gonzalez, Soderling, and Davydenko. The recent play of veteran Tommy Haas, 31, and newcomer Marin Cilic, 20, further illustrate the depth across the annual cohorts active in today's men's game. At Cincinnati, Querrey, Guccione, Berdych, and Chardy -- all in their early twenties -- scored early-round upsets over higher-ranked stars. As U.S. Open 09 now begins, it is hard to remember a Slam featuring a more attractive line-up of male contenders.
 
THE FEMALE ELITES
 
The brilliance in the men's game across its top levels is not seen in the women's, where matters have been marked by uncertainties, fading results by prime performers, premature retirements and a run of disrupting injuries, and an inability of recent newcomers to break out upward. But despite the recent incoherence, women's tennis remains supreme among women's sports worldwide, and it offers as much grist for discussion as ever.
 
One year ago, Serena Williams captured U.S. Open 2008 without losing a set. Since then, uncertainties as to Serena's knee and leg problems have persisted, but she has played in all three ensuing Slams and captured two of them (Australia and Wimbledon 09). Her lifetime Slam count now stands at eleven -- seventh-best on the women's all-time list. At 27, her chances for adding to these laurels seem strong, as the six legends ahead of her all won at least one more Slam after reaching that age. Serena's powerful serving and stroking, along with her excellent athleticism and court mobility, allow her to battle on equal terms with any of her current rivals, while her force of will seems able to produce victories on the largest stages more often than seems probable. Although Serena's performance since the last Slam, at Wimbledon, has been ragged, as often seems to happen between Slams, she remains the sport's current champion in the minds of most observers.
 
But Serena is not the leader in the official WTA current (12-month) rankings. Ahead of her in this indicator is Dinara Safina, sister of Marat, age 23 at height just under 6-0. Safina's power-based game matured a little over a year ago upon Dinara's improved conditioning, court movement, and avoidance of error. Amid a full playing schedule and a flow of good results, she reached the Final Four of the last four Slams, and she captured the clay events in Rome and Madrid 2009. Her early summer record again slumped, though she reached the final in Cincinnati in August, losing to Jankovic. She then lost her first match in Montreal.
 
The other top contenders seem closely bunched in current playing form. Jelena Jankovic, who attained the top ranking for 2008, faded through much of 2009 to date, but in capturing Cincinnati over Safina, she showed the mobility, shot-making, and tenacity seen last year. Venus Williams brings her season-ending crown at Doha 08 and her runner-up honors at Wimbledon 09 -- milestones in a fine late-career surge at age now 29. Venus's athleticism and power seem seem just as impressive as when she won U.S. Open in 2000 and 2001. Meanwhile Svetlana Kuznetsova, still just 24, won U.S. Open in 2004 and has dwelled among the top women ever since, showing plenty of power and all-around athleticism. Seeded seventh, Svetlana won Garros 09, beating Safina in the final. Probably at the head of our prime group after Serena is Elena Dementieva, 27, who has been a consistent finalist and semi-finalist throughout the past twelve months. Her performance in narrowly failing to defeat Serena in their Wimbledon semi was surely among her best ever, and she showed readiness for moving upward when she won Montreal 09, including a semi-final win over Serena. Meanwhile the recent play of Stosur, Pennetta, and Bammer suggest their readiness to challenge the top group, while young players Azarenka, Wozniacki, Kleybanova, and Lisicki also lurk.
 
Pinning down the chances of the above stars, especially Serena, at the Open defies confidence. Making matters even less comprehensible are the returns from inactivity of two superstars, Clijsters and Sharapova. Kim Clijsters rejoined tour action in early August from a two-year retirement that included childbirth. Kim won U.S. Open in 2005. Maria Sharapova, having been sidelined for nine months with shoulder trouble, returned earlier, in the spring, and contested well in losing to Dementieva in Montreal except for making too many double-faults.
 
THE PREDICTING SCHEME
 
We continue seeking better methods for predicting outcomes of Slams. Here, we will in turn examine the likely individual match-ups from the Open's official draw. In comparing the two players in each match-up, we will apply six categories of data. The player with the most credits in the six categories will become our predicted winner of that match-up:
 
-- 1. Weighted performances of the two players in leading events over the past 12 months. The weights are ascertained by how well each event has historically predicted outcomes at forthcoming U.S. Opens. (The best predictor of U.S. Open among the men has been the preceding year's U.S. Open; next-best has been Australian Open. Among the women the best predictor has been Miami/Key Biscayne; Wimbledon has been second-best.)
 
-- 2. Weighted performances of the two players in calendar year 2009 to date. Wins in Slams are weighted heaviest, etc. (For the women, data of the official WTA year-to-date race is used here; for the men we make an unofficial compilation, as ATP no longer publishes year-to-date standings.)
 
-- 3. Standings of the two players in Olympus U.S. Open Series 09, as officially announced. (Note that in each of our first three categories, above, full credit is given if the numerical margin between the two opponents is at least ten percent; half credit is given if the margin is less, except that no credit is given if the margin is less than one percent.)
 
-- 4. Outcome of the most recent head-to-head meeting between the two players.
 
-- 5. Outcome in all head-to-head meetings between the two players in 2008 and 2009 prior to the last meeting. (A half-credit is given if the plurality of wins in this category is only one.)
 
-- 6. Youth. The younger of the two players on average should be improving faster (or declining slower) than the older player subsequent to the past results used here as predictors. (No credit is given if the age difference is less than one year; a half-credit is given if the age difference is 1-2 years.)
 
If a tiebreaker is needed, the second category is devalued slightly. (This category is somewhat redundant with the first and third, and also it may overweight clay results.) There is also an Overrule Proviso: If flaws in the scheme produce an apparently untenable match-winner, we may -- indeed will be expected to -- overrule the stated verdict. The penalty for an incorrect reversal will be to confess the blunder in the next column published in Tennis Server here just after the Open.
 
PREDICTING TOP QUARTER, MEN'S SINGLES
 
Roger Federer seems comfortable in this quarter. Soderling showed at Garros and Wimbledon that at his best he can defeat anyone. Davydenko has been trending upward.
 
-- Robredo over Blake.
 
-- Federer over Robredo. Roger is ahead in all indicator categories except youth. His career head-to-head edge over Tommy is 8-0.
 
-- Soderling over Querrey. Robin leads by 3.5-2 credits in the several indicators, where Sam scores well as overall leader in U.S. Open Series. Sam's potent forehand and serve could make big trouble for any player, certainly for Robin.
 
-- Davydenko over Soderling. The advantage for Davydenko is narrow at 2.5-2. Nicolay leads for 2009 to date despite Robin's fine performance in the springtime Slams.
 
-- Federer over Davydenko. Roger ahead or even in all categories.
 
SECOND QUARTER
 
Two Big Sixers are here, Djokovic and Roddick, with neither in serious jeopardy prior to their inevitable meeting in the tournament quarter-finals.
 
-- Stepanek over Kohlschreiber. Radek is comfortably ahead in the first three categories, the head-to-head credit is neutral, and the youth credit goes to the German player. An extended struggle between two European near-champions could ensue.
 
-- Djokovic over Stepanek. Novak leads or is even in all categories.
 
-- Djokovic over Roddick. Andy won their most-recent meeting, at Montreal 09, and has the edge in the previous three meetings, which included a win at U.S. Open 08 when Novak retired. But the stronger performance of Novak through 2008 and 2009 outweighs these indicators here.
 
THIRD QUARTER
 
Despite the recent knee trouble, Nadal should rule this quarter over several French stars (Monfils, Llodra, Tsonga, Chardy) plus Gonzalez and Berdych. Fernando should be the primary threat, but our scheme makes him a loser to tall Berdych.
 
-- Berdych over Gonzalez. Fernando shows the greater success since last year's Open, but Berdych leads in head-to-head wins, including at Cincinnati 09 where Gonzo retired. Tomas's youth credit swings the choice his way.
 
-- Tsonga over Berdych. These two are close in most categories but Jo-Wilfried leads conclusively in performance over the last 12 and 8 months.
 
-- Monfils over Chardy. Chardy is a strong young player but is well behind in overall record.
 
-- Monfils over Ferrer. The margin is close here as well, but Gael's credit for youth makes the difference.
 
-- Nadal over Llodra.
 
-- Nadal over Monfils. Rafa is ahead or even in all indicator categories.
 
BOTTOM QUARTER
 
This is the other quarter having two Top Sixers, Murray and del Potro. Young Cilic could make trouble for anyone on the fast courts but our scheme has Wawrinka eliminating him. Gilles Simon's spring-and-summer record has been indifferent.
 
-- Simon over Ferrero. Juan Carlos won their meeting at Wimbledon 09 but otherwise the credentials of Simon are too good.
 
-- del Potro over Simon. The tall Argentine prevailed when they met a year ago at Flushing Meadows and should do so again.
 
-- Wawrinka over Cilic. The margin is close, where Stan's lead in the 12-month category decides.
 
-- Murray over Karlovic.
 
-- Murray over Wawrinka. Andy ahead in all measures, including a win in their Wimbledon 09 meeting.
 
-- Murray over del Potro. The tally is 4.5-1.5, including a full credit for Andy's head-to-head win at Cincinnati 09 and a half credit for a close edge in U.S. Open Series 09.
 
FINAL FOUR
 
So far, our mini-analyses have served to confirm the superiority of the Big Four, including the narrow edge of that elite group over the other Big Six members. Now, the scheme faces the more difficult challenge of untangling the Four.
 
-- Semi-final: Nadal over Murray. The two are within one year in age, so no youth credit is awarded. Murray leads in the first indicator, 12-month performance, balanced by Nadal's lead in the second, 2009 to date performance. (Note that Rafa's big superiority in clay results has greater importance in the second category than in the first, where weighting is based on past correlations among tournaments.) Murray receives a full credit for leading in U.S. Open Series. Rafa, however, receives full credit in both head-to-head categories, having won their most recent meeting and four of the preceding six. Note, however, that the two are even on hard courts during 2008-09, at two wins each.
 
-- Semi-final. Federer over Djokovic. Roger's leads in the first three categories as well as in the most recent head-to-head meeting, where he convincingly defeated Novak at Cincinnati.
 
-- Final. Federer over Nadal. Roger leads in four indicators, including most recent head-to-head. (He beat Rafa at Madrid 09 on clay.) Rafa obtains credit for earlier head-to-head play, having won their preceding five meetings, and for youth. Judgment suggests that if Roger plays his best attacking game, the actual verdict of this yet-another classic final will coincide with that of our scheme.
 
Our winding path has brought us to the almost universal conclusion taken from the final weekend at Cincinnati -- that Sir Roger remains atop our great sport.
 
TOP QUARTER, WOMEN'S SINGLES
 
Plenty of dangers in this quarter face the tournament's #1 women's seed, Dinara Safina, including the survivor of Razzano vs. Schnyder, and eventually the survivor of Lisicki, Jankovic, and Ivanovic.
 
-- Razzano over Schnyder. Patty is the higher seeded player, but the French star comes out ahead, albeit closely, in all six of our indicator categories.
 
-- Safina over Razzano. Head-to-head data are lacking, but Dinara shows by far the better winning record otherwise.
 
-- Ivanovic over Lisicki. The young German with the superior serve is not far behind and indeed claims the youth credit, but Ivanovic's 2009 record, though it has been disappointing after her earlier success, is enough to create the edge in her favor here.
 
-- Jankovic over Ivanovic. Our margin favors Jankovic by one-half credit.
 
-- Safina over Jankovic. Jelena won their recent head-to-head in Cincinnati and shows a clear edge in U.S. Open Series. But behind a stronger year-long performance and also the youth credit, Dinara becomes our predicted winner.
 
SECOND QUARTER
 
If she can survive an early meeting with Sharapova, Elena Dementieva should be safe here.
 
-- Dementieva over Sharapova. Elena's narrow head-to-head win over Maria at Cincinnati validates her primacy here. Without that recent result, the Overrule Proviso would probably be invoked here in recognition that Sharapova's record is marred by her long absence with shoulder trouble, now apparently overcome.
 
-- Dementieva over Petrova.
 
-- Wozniacki over Cirstea. The margin between these rising teenagers is narrow, and indeed Cirstea holds the most recent victory over the other, at Los Angeles 09.
 
-- Wozniacki over Kuznetsova. Lacking head-to-head data, this comparison results in a tie, which by rule is broken by devaluing the Garros 09 champion's surprisingly small edge in 2009 play to date.
 
--Dementieva over Wozniacki. Elena's decisive win over Caroline in Cincinnati cements this verdict.
 
THIRD QUARTER
 
The presence of Kim Clijsters in this section largely invalidates our scheme, which gives considerable heed to performance prior to this summer. Azarenka, Bartoli, and Venus Williams all outscore Kim in our full scheme, but Kim's strong play in the two principal events since Wimbledon -- Cincinnati and Toronto -- require use of the Overrule Proviso here.
 
-- Azarenka over A. Radwanska. Victoria trails Agnieszka in U.S. Open Series to date but is otherwise clearly ahead.
 
-- Clijsters over Bartoli. Kim's straight-set win over Marion at Cincinnati 09 requires use of the Overrule Proviso here.
 
-- Clijsters over V. Williams. There has been no recent head-to-head meeting, though Kim won their last two prior to her retirement from the sport, both on hard courts. Kim also claims the youth credit. The margin for overrule is obviously narrow, but Kim's stronger run in August rules.
 
-- Clijsters over Azarenka. Kim defeated Victoria at Toronto in three sets, 61 in the third, to validate use of the Overrule Proviso again here.
 
BOTTOM QUARTER
 
Serena's edge here would seem overwhelming, she having won two of the year's three Slams to date. Pennetta and Stosur have been showing strong results of late, however, and veterans Hantuchova and Mauresmo have good weaponry. Zvonareva with a bad ankle is not a factor.
 
-- Pennetta over Mauresmo. Amelie won in their most recent meeting, at Wimbledon this year, but all other indicators point to Pennetta, including their earlier head-to-head record.
 
-- Stosur over Hantuchova.
 
-- S. Williams over Stosur. The six indicators are divided three-each. The tie goes to Stosur by our stated method, but the Overrule Proviso is invoked here in view of Serena's often-seen intangibles.
 
-- S. Williams over Pennetta. Flavia wins the credit for U.S. Open Series and for youth. But Serena has the others including the most recent head-to-head win.
 
FINAL FOUR
 
Having invoked the Overrule Proviso twice, thereby enabling Clijsters and Serena to reach our predicted semis, we tend to let the chips fall as they may henceforth.
 
-- Semi-final: Safina over Dementieva. Although Dementieva has seemed the stronger of the two this summer, our scheme predicts differently, by margin 3.5 to 2.5. The temptation to overrule is strong, as Dementieva gains in the comparison on hard courts. Either player could win, where the winner will be the one closest to her top game.
 
-- Semi-final: S. Williams over Clijsters. Serena prevails, even in our U.S. Open Series indicator where Clijsters participated significantly.
 
-- Final: Safina vs. S. Williams. Here are the verdicts in each predicting category:
 

-- #1. Twelve-month performance: Safina leads but by margin less than ten percent. One-half credit to Safina.
-- #2. Year 2009 to date: Safina leads. One credit to Safina.
-- #3. U.S. Open Series: Serena leads but by margin less than ten percent. One-half credit to Serena.
-- #4. Most recent head-to-head. Serena won at Australian Open 09. One credit to Serena.
-- #5. Earlier head-to-heads in 2008-09. Serena won two of three. One-half credit to Serena.
-- #6. Youth. One credit to Safina.