AP Photo/Charles Krupa
Kim Clijsters, of Belgium, holds the trophy after winning the women's championship over Caroline Wozniacki, of Denmark, at the U.S. Open tennis tournament in New York, Sunday, Sept. 13, 2009.
AP Photo/Darron Cummings
Novak Djokovic, of Serbia, serves to Roger Federer, of Switzerland, during their semifinals match at the U.S. Open tennis tournament in New York, Sunday, Sept. 13, 2009.
AP Photo/Darron Cummings
Roger Federer, of Switzerland, in action against Novak Djokovic, of Serbia, during their semifinals match at the U.S. Open tennis tournament in New York, Sunday, Sept. 13, 2009.
AP Photo/Darron Cummings
Juan Martin del Potro, of Argentina, pumps his fist during his semifinals match against Rafael Nadal, of Spain, at the U.S. Open tennis tournament in New York, Sunday, Sept. 13, 2009.
AP Photo/Charles Krupa
Rafael Nadal, of Spain, reacts after losing a point to Juan Martin del Potro, of Argentina, during their semifinals match at the U.S. Open tennis tournament in New York, Sunday, Sept. 13, 2009. Del Potro won 6-2, 6-2, 6-2.
AP Photo/Charles Krupa
Kim Clijsters, of Belgium, hits balls to spectators after winning her semifinals match against Serena Williams, of the United States, at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Charles Krupa
Serena Williams, of the United States, left, talks to officials after arguing with a line judge over a foot fault during her match against Kim Clijsters, of Belgium, at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009. Clijsters defeated Williams in two sets.
AP Photo/Elise Amendola
Caroline Wozniacki, of Denmark, lunges to return a shot to Yanina Wickmayer, of Belgium, during their match at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009. Wozniacki won 6-3, 6-3.
AP Photo/Elise Amendola
Yanina Wickmayer, of Belgium, returns a shot to Caroline Wozniacki, of Denmark, in a near-empty Louis Armstrong Stadium during their match at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Kathy Willens
A video screen with the U.S. Open logo is reflected on the court at Louis Armstrong Stadium during a rain delay at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Elise Amendola
A spectator sits in Louis Armstrong Stadium during a rain delay at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Darron Cummings
Rafael Nadal, of Spain, reacts after defeating Fernando Gonzalez, of Chile, in three sets in their quarterfinals match at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Charles Krupa
Golfer Greg Norman, from Australia, looks at a digital image on the back of a photographer's camera during a quarterfinals match between Fernando Gonzalez, of Chile, and Rafael Nadal, of Spain, at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Charles Krupa
Fernando Gonzalez, of Chile, hits a forehand to Rafael Nadal, of Spain, during their quarterfinals match at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Charles Krupa
Rafael Nadal, of Spain, hits a shot to Fernando Gonzalez, of Chile, during their quarterfinals match at the U.S. Open tennis tournament in New York, Saturday, Sept. 12, 2009.
AP Photo/Charles Krupa
The tennis court in Arthur Ashe Stadium is reflected in raindrops at the U.S. Open tennis tournament in New York, Friday, Sept. 11, 2009. Play for the day was postponed due to inclement weather.
AP Photo/Charles Krupa
A spectator struggles with her umbrella while waiting for play to begin at the U.S. Open tennis tournament in New York, Friday, Sept. 11, 2009. Play for the day was postponed due to inclement weather.
AP Photo/Darron Cummings
Workers squeegee the court in Arthur Ashe Stadium before the start of play at the U.S. Open tennis tournament in New York, Friday, Sept. 11, 2009.