LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia serves during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia serves during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

Russia's Nikolay Davydenko celebrates after winning his ATP World Tour Finals tennis match against Spain's Rafael Nadal at the O2 Arena in London, Wednesday Nov. 25, 2009.

Russia's Nikolay Davydenko returns a ball during his ATP World Tour Finals tennis match against Spain's Rafael Nadal at the O2 Arena in London, Wednesday Nov. 25, 2009.

Nikolay Davydenko of Russia plays against Spain's Rafel Nadal in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

Nikolay Davydenko of Russia plays against Spain's Rafel Nadal in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Nikolay Davydenko of Russia plays against Spain's Rafel Nadal in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Nikolay Davydenko of Russia celebrates after beating Spain's Rafel Nadal 6-1 7-6 (7-4) in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Nikolay Davydenko of Russia celebrates after beating Spain's Rafel Nadal 6-1 7-6 (7-4) in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Nikolay Davydenko of Russia celebrates after beating Spain's Rafel Nadal 6-1 7-6 (7-4) in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

Russia's Nikolay Davydenko serves the ball to Spain's Rafael Nadal during their ATP World Tour Finals tennis match at the 02 Arena in London, Wednesday, Nov. 25, 2009.

Russia's Nikolay Davydenko returns the ball to Spain's Rafael Nadal during their ATP World Tour Finals tennis match at the 02 Arena in London, Wednesday, Nov. 25, 2009.

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Matthew Lewis/Getty Images for Barclays ATP Finals)

Russia's Nikolay Davydenko reacts to his win against Spain's Rafael Nadal during their ATP World Tour Finals tennis match at the 02 Arena in London, Wednesday, Nov. 25, 2009.

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia celebrates winning the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia celebrates winning the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

Nikolay Davydenko of Russia plays against Rafael Nadal of Spain in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

Nikolay Davydenko of Russia plays against Rafael Nadal of Spain in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Matthew Lewis/Getty Images for Barclays ATP Finals)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia serves the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia serves the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia arrives to the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

Nikolay Davydenko of Russia plays against Rafael Nadal of Spain in a Singles match during the Barclays ATP World Tour Tennis Finals in London, on November 25, 2009. AFP PHOTO/GLYN KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia serves during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 25: Nikolay Davydenko of Russia returns the ball during the men's singles first round match against Rafael Nadal of Spain during the Barclays ATP World Tour Finals at the O2 Arena on November 25, 2009 in London, England. (Photo by Julian Finney/Getty Images)