The U.S. Open has made things very interesting at the top of tennis.
For just the second time in 10 years, neither of the top two seeds took home the title—that honour went to third-seeded Andy Murray. It leaves the top two ranked players, Roger Federer and Novak Djokovic, locked in a struggle for year-end supremacy.
Federer had gained the top spot after winning Wimbledon and needed a strong showing over the following few weeks to stand any chance of maintaining it.
Let us not forget the significance finishing the year with the ranking has always had for Federer, who has in fact never failed to retain the year-end ranking after having gained it. He chases history—aiming to tie Pete Sampras as the only man to have finished ranked No. 1 for six years.
Sampras' record will probably remain unbroken for a long time, because he held the year-end ranking six years in a row.
But six, still, must surely be Federer's goal deep in his heart.
The man who does stand a chance of equalling Pete Sampras is Novak Djokovic. He finished the rankings leader in 2011, having won just about everything but the Barclays ATP World Tour Finals.
He has had a tough time following it up, defending only his Australian Open crown, of the three he captured last year, and in losing the U.S. Open final lost quite a few ranking points, as well.
The struggle for the No. 1 ranking begins in this post-U.S. Open period, because Federer and Djokovic enjoyed differing fortunes at this stage of 2011.
After losing to Djokovic in the U.S. Open semifinals last year, Federer raced away with an unbroken streak and a string of three straight titles at Basel, Paris and London. A year later, some of this success comes back to haunt him—he has some 3,000 points to defend for the rest of the season.
Djokovic's victory at the U.S. Open in 2011 saw him at the peak of his powers, but it failed to propel him any higher.
As they say, there is nowhere but down to go at the very top, and that is where Djokovic went—a stunning loss in the Basel semifinal (dropping a bagel to Kei Nishikori) was followed up by a quarterfinal withdrawal at the Paris Masters and a disappointing World Tour Finals in London, where he lost two matches (thereby marring at the last hour an impeccable season win-loss record).
He, thus, has only 560 points to defend.
Federer leads Djokovic by nearly 1,500 points at this moment, but the points differential between now and the close of the 2012 season is 1,000 points more than that.
What it means essentially is that, for Federer to remain top dog, he will have to repeat his heroics of last year and hope at the same time that Djokovic manages nothing better than a final at Basel or Paris. A lot could hinge on either man's performance at the year-end championships, where Djokovic has more than 1,000 points to gain and Federer, the same amount to lose.
It is possible that Djokovic could go on another end-year slide, but nothing suggests in his results of late that he should have anywhere near the same reasons as last year to do so. It just makes the next Masters Series event at Shanghai all the more significant, because neither Djokovic nor Federer played there last year, and they both have much to gain there this year.
The race for the year-end No. 1 ranking is likely to be decided there and at the Barclays World Tour Finals.