...NOVEMBER 28: Roger Federer of Switzerland reacts during the men's singles semi final match against Nikolay Davydenko of Russia during the Barclays ATP World Tour Finals at the O2 Arena on November 28...

LONDON, ENGLAND - NOVEMBER 29: Nikolay Davydenko of Russia serves the ball during the men's singles final match against Juan Martin Del...

Nikolay Davydenko of Russia celebrates after beating Roger Federer of Switzerland 6-2 4-6 7-5 in...

...26, 2009 in London, England (Photo by Clive Brunskill/Getty Images) 2- : LONDON, ENGLAND - NOVEMBER 27: Nikolay Davydenko of Russia returns the ball during the men's singles round robin match against Robin Soderling...

Rafael Nadal of Spain reacts as he lost a point against Nikolay Davydenko of Russia during the singles final match of Shanghai ATP Masters 1000 tennis tournament at Qizhong...

Nikolay Davydenko of Russia kisses the winner's trophy after defeating Rafael Nadal of Spain in the men...

Nikolay Davydenko of Russia smiles as he looks to his wife Irina in the stands following victory over...

Fabrice Santoro, of France, uses both hands to hit a return to Russia's Nikolay Davydenko in a second round singles match at the Pilot Pen tennis tournament in New Haven, Conn...

1- May 10, 2009; Lisbon, PORTUGAL; Nikolay Davydenko (RUS) returns a shot against James Blake (USA), not pictured, during the semifinals of the Estoril...

HAMBURG, GERMANY - JULY 26: Nikolay Davydenko of Russia celebrates after winning the match against Paul Henri Mathieu of France during day seven...

HAMBURG, GERMANY - JULY 23: Nikolay Davydenko of Russia returns the ball during the match against Jeremy Chardy of France during day four...

BARCELONA, SPAIN - APRIL 25: Rafael Nadal of Spain celebrates his win over Nikolay Davydenko of Russia on day six of the ATP 500 World Tour Barcelona Open Banco Sabadell 2009...

Rafael Nadal of Spain returns the ball to Nikolay Davydenko of Russia during their match in the Barcelona Open Tennis tournament in Barcelona, Spain, Saturday, April...

Nikolay Davydenko of Russia returns the ball to Czech Republic's Radek Stepanek during their Barcelona Open Tennis...

Nikolay Davydenko of Russia returns the ball to his compatriot Igor Andreev at the ABN Amro tennis tournament...