2011 U.S. Open tennis tournament

Novak Djokovic kisses the trophy after winning the men's championship — AP Photo/Charles Krupa

Novak Djokovic of Serbia kisses the trophy after winning the men's championship match against Rafael Nadal of Spain at the U.S. Open tennis tournament in New York, Sept. 12, 2011.

Novak Djokovic kisses the court after winning the men's championship match — AP Photo/Charles Krupa

Novak Djokovic of Serbia kisses the court after winning the men's championship match against Rafael Nadal of Spain at the U.S. Open tennis tournament in New York, Sept. 12, 2011.

Rafael Nadal of Spain reacts during the championship match against Novak Djokovic of Serbia at the U.S. Open tennis tournament in New York, Sept. 12, 2011.

Novak Djokovic returns a shot to Rafael Nadal — AP Photo/Elise Amendola

Novak Djokovic of Serbia returns a shot to Rafael Nadal of Spain during the men's championship match at the U.S. Open tennis tournament in New York, Sept. 12, 2011.

Samantha Stosur of Australia poses with the championship trophy after beating Serena Williams at the U.S. Open tennis tournament in New York, Sept. 11, 2011.

Samantha Stosur of Australia reacts after winning the women's championship match against Serena Williams at the U.S. Open tennis tournament in New York, Sept. 11, 2011.

Serena Williams argues with chair umpire Eva Asderaki — AP Photo/Matt Slocum

Serena Williams, left, argues with chair umpire Eva Asderaki during the women's championship match against Samantha Stosur of Australia at the U.S. Open tennis tournament in New York, Sept. 11, 2011.

Novak Djokovic of Serbia reacts after winning a semifinal match against Roger Federer of Switzerland at the U.S. Open tennis tournament in New York, Saturday, Sept. 10, 2011.

Rafael Nadal of Spain returns a shot to Andy Roddick during a quarterfinal match at the U.S. Open tennis tournament in New York, Friday, Sept. 9, 2011.

Roger Federer of Switzerland reacts after winning the first set against Novak Djokovic of Serbia during a semifinal match at the U.S. Open tennis tournament in New York, Saturday, Sept. 10, 2011.

Novak Djokovic of Serbia reacts while playing Roger Federer of Switzerland during a semifinal match at the U.S. Open tennis tournament in New York, Saturday, Sept. 10, 2011.

Andy Roddick reacts during a quarterfinal match against Rafael Nadal of Spain at the U.S. Open tennis tournament in New York, Friday, Sept. 9, 2011.

Rafael Nadal of Spain serves to Andy Roddick during a quarterfinal match at the U.S. Open tennis tournament in New York, Friday, Sept. 9, 2011.

Roger Federer sits on a chair under an umbrella during a rain delay — AP Photo/Charles Krupa

Roger Federer, of Switzerland, sits on a chair under an umbrella during a rain delay in his quarterfinal match against Jo-Wilfried Tsonga, of France, at the U.S. Open tennis tournament in New York, on Thursday, Sept. 8, 2011.

Serena Williams reacts during her semifinal match against Caroline Wozniacki of Denmark at the U.S. Open tennis tournament in New York, Saturday, Sept. 10, 2011.

Serena Williams reacts during a match against Anastasia Pavlyuchenkova of Russia during a quarterfinals match at the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

Angelique Kerber of Germany reacts after winning her quarterfinal match against Flavia Pennetta of Italy at the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

John Isner reacts after winning his match against Gilles Simon of France during the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

Andy Murray serves to Donald Young — AP Photo/Matt Slocum

Andy Murray of Great Britain serves to Donald Young of USA during the fourth round at the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

David Ferrer returns to Andy Roddick — AP Photo/Charles Krupa

David Ferrer of Spain returns to Andy Roddick of USA during the fourth round at the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

Andy Murray returns to Donald Young — AP Photo/Charles Krupa

Andy Murray, of Great Britain, returns to Donald Young during a match at the U.S. Open tennis tournament in New York, on Thursday, Sept. 8, 2011.

Andy Roddick serves — AP Photo/Charles Krupa

Andy Roddick of USA serves to David Ferrer of Spain during the fourth round at the U.S. Open tennis tournament in New York, Thursday, Sept. 8, 2011.

Roger Federer returns to Juan Monaco — AP Photo/Elise Amendola

Roger Federer, of Switzerland, returns to Juan Monaco, of Argentina, in the fourth round of the U.S. Open tennis tournament, Tuesday, Sept. 6, 2011, in New York.

Juan Monaco returns to Roger Federer — AP Photo/Elise Amendola

Juan Monaco, of Argentina, returns to Roger Federer, of Switzerland, in the fourth round of the U.S. Open tennis tournament in New York, Tuesday, Sept. 6, 2011.

Fans wait for autographs during the U.S. Open tennis tournament, Monday, Sept. 5, 2011, in New York.

Roger Federer flashes a thumbs up to the crowd — AP Photo/Charles Krupa

Roger Federer, of Switzerland, flashes a thumbs up to the crowd after beating Juan Monaco, of Argentina, 6-1, 6-2, 6-0 during the U.S. Open tennis tournament in New York, Tuesday, Sept. 6, 2011.

Novak Djokovic reacts — AP Photo/Paul J. Bereswill

Novak Djokovic of Serbia reacts during his match against Alexandr Dolgopolov of the Ukraine during the U.S. Open tennis tournament in New York, Monday, Sept. 5, 2011.

Caroline Wozniacki grips the tennis ball — AP Photo/Charles Krupa

Caroline Wozniacki, of Denmark, grips the tennis ball as she prepares to serve against Svetlana Kuznetsova, of Russia, during the U.S. Open tennis tournament in New York, Monday, Sept. 5, 2011.

Janko Tipsarevic of Serbia serves to Juan Carlos Ferrero of Spain during the U.S. Open tennis tournament in New York, Monday, Sept. 5, 2011.

Rafael Nadal returns a shot — AP Photo/Charlie Riedel

Rafael Nadal of Spain returns a shot to David Nalbandian of Argentina during the U.S. Open tennis tournament in New York, Sunday, Sept. 4, 2011.

Angelique Kerber of Germany reacts after winning her match against Monica Niculescu of Romania during the U.S. Open tennis tournament in New York, Sunday, Sept. 4, 2011.

Sabine Lisicki, of Germany, reacts after losing a point during the second set against Vera Zvonareva, of Russia, during the U.S. Open tennis tournament in New York, Sunday, Sept. 4, 2011.

Donald Young reacts during his match against Juan Ignacio Chela of Argentina during the U.S. Open tennis tournament in New York, Sunday, Sept. 4, 2011.

Novak Djokovic, of Serbia, returns to Nikolay Davydenko, of Russia, during the third round of the U.S. Open tennis tournament in New York, Saturday, Sept. 3, 2011.

Serena Williams reacts during her match against Victoria Azarenka of Belarus during the U.S. Open tennis tournament in New York, Saturday, Sept. 3, 2011.

Francesca Schiavone of Italy reacts after defeating Chanelle Scheepers of South Africa during the U.S. Open tennis tournament in New York, Saturday, Sept. 3, 2011.

Lucie Safarova of the Czech Republic, keeps her eyes on the ball during a match against Monica

Donald Young reacts after winning his match against Stanislas Wawrinka of Switzerland during the U.S. Open tennis tournament in New York, Friday, Sept. 2, 2011.

In this photo shot with a fisheye lens Maria Sharapova of Russia adjusts the strings of her racket during her match against Flavia Pennetta of Italy during the U.S. Open tennis tournament in New York, Friday, Sept. 2, 2011.

Juan Martin Del Potro of Argentina reacts during his match against Diego Junqueira of Argentina during the U.S. Open tennis tournament in New York, Friday, Sept. 2, 2011.

Maria Kirilenko, of Russia, keeps her eyes on the ball as she returns against Christina McHale, of the United States, during the U.S. Open tennis tournament on Friday, Sept. 2, 2011, in New York.

Andrea Petkovic of Germany serves against Jie Zheng of China during Day Four of the U.S. Open tennis tournament at the USTA Billie Jean King National Tennis Center on Sept. 1, 2011 in New York City.

Number three seed Roger Federer of Switzerland returns a shot to Dudi Sela of Israel during a Men's single match at the U.S. Open tennis tournament on Sept. 1, 2011 at the Billie Jean King National Tennis Center in New York.

USTA Billie Jean King National Tennis Center — Getty Images/Julian Finney

Juan Carlos Ferrero of Spain, right, returns a shot against Gael Monfils of France during Day Four of the U.S. Open tennis tournament at the USTA Billie Jean King National Tennis Center on Sept. 1, 2011 in New York City.

Serena Williams of the U.S. returns a shot to Michaella Krajicek of Netherlands during a Women's singles match at the US Open tennis tournament, Sept. 1, 2011 at the Billie Jean King National Tennis Center in New York.

Serbian tennis player Novak Djokovic returns a shot to Argentina's Carlos Berlocq during their U.S. Open tennis tournament match at the USTA Billie Jean King National Tennis Center in New York, Sept. 1, 2011.

Gael Monfils of France dives to return a shot by Juan Carlos Ferrero of Spain during the U.S. Open tennis tournament in New York, Sept. 1, 2011.

Andrea Petkovic serves to Zheng Jie — AP Photo/Charlie Riedel

Andrea Petkovic of Germany serves to Zheng Jie of China during the U.S. Open tennis tournament in New York, Sept. 1, 2011.

Maria Sharapova blows a kiss to the crowd — AP Photo/Charles Krupa

Maria Sharapova, of Russia, blows a kiss to the crowd after beating Anastasiya Yakimova, of Belarus, 6-1, 6-1 during the U.S. Open tennis tournament in New York, early Thursday morning, Sept. 1, 2011.

Andy Murray serves to Somdev Devvarman — AP Photo/Charlie Riedel

Andy Murray of Britain serves to Somdev Devvarman of India during the U.S. Open tennis tournament in New York, Wednesday, Aug. 31, 2011.

Irina Falconi leaps in the air after beating Dominka Cibulkova — AP Photo/Charles Krupa

Irina Falconi, of the United States, leaps in the air after beating Dominka Cibulkova, of Slovakia, during the U.S. Open tennis tournament in New York, Wednesday, Aug. 31, 2011. Falconi won 2-6, 6-3, 7-5.

Angelique Kerber celebrates victory — AP Photo/Elise Amendola

Angelique Kerber, of Germany, celebrates her 6-3, 4-6, 6-3 upset victory over Agnieszka Radwanska, of Poland, during the second round of the U.S. Open tennis tournament in New York, Wednesday, Aug. 31, 2011.

Anabel Medina Garrigues of Spain reacts after defeating Laura Robson, of Britain, during the U.S. Open tennis tournament in New York, Wednesday, Aug. 31, 2011.

Andrey Golubev serves to Rafael Nadal of Spain during the first round of the U.S. Open tennis tournament in New York, Tuesday, Aug. 30, 2011.

Ana Ivanovic of Serbia reacts during her match against Ksenia

Agnieszka Radwanska of Poland serves to Urszula

Caroline

David Ferrer of Spain returns a shot to Igor

Rafael Nadal, of Spain, celebrates his 6-3, 7-6 (1), 7-5 victory over Andrey Golubev, of Kazakhstan, during the first round of the U.S. Open tennis tournament in New York, Tuesday, Aug. 30, 2011.

Gael Monfils, of France, volleys the ball to Grigor Dimitrov, of Bulgaria, during the first round of the U.S. Open tennis tournament in New York, Aug. 29, 2011.

The shadow of Julia Goerges of Germany appears on the court as she serves to Kristina Barrois of Germany during the first round of the U.S. Open tennis tournament in New York, Aug. 29, 2011.

Tomas Berdych serves — AP Photo/Elise Amendola

Tomas Berdych of the Czech Republic serves to Romain Jouan of France during the first round of the U.S. Open tennis tournament in New York, Aug. 29, 2011.

Alejandro Falla reacts after playing Viktor Troicki — AP Photo/Elise Amendola

Alejandro Falla of Colombia reacts after playing Viktor Troicki of Serbia during the first round of the U.S. Open tennis tournament in New York, Aug. 29, 2011.