Roger Federer of Switzerland plays against Fernando Verdasco of Spain in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 22, 2009

...press conference at the Davidoff Swiss Indoors tennis tournament in Basel, Switzerland, Sunday, Nov. 1, 2009. The ATP tournament will last until Sunday, Nov. 8, 2009. (AP Photo/Keystone/Georgios Kefalas

Serbian Novak Djokovic celebrates his victory over French Gael Monfils at the end of their Paris Masters ATP tournament final tennis match on November 15, 2009 at the 'Palais Omnisports de Paris Bercy' in Paris...

...Murray of Great Britain in action during his match against Radek Stepanek of Czech Republic during the ATP Masters Series at the Palais Omnisports De Paris-Bercy on November 12, 2009 in Paris, France. (Photo...

PARIS - NOVEMBER 11: Roger Federer of Switzerland hits an overhed against Julien Benneteau of France during the ATP Masters Series at the Palais Omnisports De Paris-Bercy on November 11, 2009 in Paris, France. (Photo...

Serbian Novak Djokovic celebrates his victory over French Gael Monfils at the end of their Paris Masters ATP tournament final tennis match on November 15, 2009 at the 'Palais Omnisports de Paris Bercy' in Paris...

Serbian Novak Djokovic celebrates his victory over French Gael Monfils at the end of their Paris Masters ATP tournament final tennis match on November 15, 2009 at the 'Palais Omnisports de Paris Bercy' in Paris...

...the ball to Czech Republic's Radek Stepanek during the semi final match at the Swiss Indoors ATP tennis tournament on November 7, 2009 in Basel. Djokovic won 6-7 (4/7), 7-5, 6...

...Republic's Radek Stepanek (out of camera range) during their semi-final match at the Swiss Indoors ATP tennis tournament on November 7, 2009 in Basel. AFP PHOTO / FABRICE COFFRINI (Photo credit should read FABRICE...

...Spanish Rafael Nadal eyes the ball during his quarterfinal match of the ATP Madrid Open claycourt tournament against Spanish Fernando Verdasoon May 15, 2009. Nadal won 6-4, 7-5...

...Roddick receives treatment from medical personnel during a match against Stanislas Wawrinka of Switzerland at the Shanghai ATP Masters 1000 tennis tournament in Shanghai, China, Tuesday, Oct. 13, 2009. Roddick retired in the first set...

...as he lost a point against Nikolay Davydenko of Russia during the singles final match of Shanghai ATP Masters 1000 tennis tournament at Qizhong Stadium Sunday, Oct. 18, 2009 in Shanghai, China. Davydenko won 7...

...winner's trophy after defeating Rafael Nadal of Spain in the men's singles final at the ATP Shanghai Masters tennis tournament in Shanghai on October 18, 2009. Davydenko defeated top-seeded Nadal 7-6...

...the stands following victory over Rafael Nadal of Spain in the men's singles final at the ATP Shanghai Masters tennis tournament in Shanghai on October 18, 2009. Davydenko defeated Nadal 7-6 (7/3...

...hits a backhand return against James Blake of the US during their second round match at the ATP Masters tennis tournament in Shanghai on October 14, 2009. Nadal defeated Blake 6-2, 6-7 (7...