Spain's Rafael Nadal arrives to the court to play Britain's Andy Murray in a semifinal single tennis match of the ATP World Tour Finals at O2 Arena in London, Saturday, Nov. 27, 2010. (AP Photo/Sang Tan)
Britain's Andy Murray reacts to losing a point against Spain's Rafael Nadal during their semifinal single tennis match of the ATP World Tour Finals at O2 Arena in London, Saturday, Nov. 27, 2010. (AP Photo/Sang Tan)
Spanish tennis player Rafael Nadal is seen after attending a reception with the British Prime Minister at Downing Street in London, Thursday, Nov. 18, 2010. The ATP World Tour tennis finals will be held in London at the O2 Arena starting Sunday, Nov. 22. (AP Photo/Kirsty Wigglesworth)
Rafael Nadal of Spain return the ball to compatriot Guillermo Garcia-Lopez during their semifinal match at the PTT Thailand Open tennis tournament in Bangkok, Thailand, Saturday, Oct . 2, 2010. Top-ranked Nadal was defeated by 53rd-ranked Garcia-Lopez 2-6, 7-6, 6-3. (AP Photo/Wason wanichakorn)
Tennis players Roger Federer, left, and Rafael Nadal look on during Arthur Ashe Kids Day at the USTA Billie Jean King National Tennis Center on Saturday, Aug. 28, 2010 in New York. (AP Photo/Evan Agostini)
ASSOCIATED PRESS Rafael Nadal bites the trophy, after defeating Tomas Berdych in the men's singles final on the Centre Court at the All England Lawn Tennis Championships at Wimbledon, Sunday, July 4, 2010.
** FILE ** In this May 16, 2010, file photo, Rafael Nadal, right, and Roger Federer, left, talk during the podium ceremony of the Madrid Open tennis tournament final in Madrid. Nadal won 6-4, 7-6. (AP Photo/Angel Navarrete)