Nikolay Davydenko of Russia plays against Roger Federer of Switzerland in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London. Davydenko stunned Federer to reach the final of the ATP World Tour Finals with a 6-2, 4-6, 7-5 victory over the world number one.

Roger Federer of Switzerland addresses a press conference after losing to Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Switzerland"s Roger Federer returns to Russia's Nikolay Davydenko during their ATP World Tour Finals semifinal tennis match at the O2 Arena in London, Saturday Nov. 28, 2009. (THE ASSOCIATED PRESS/Sang Tan)

Roger Federer of Switzerland looks upwards as he plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/IAN KINGTON (Photo credit should read IAN KINGTON/AFP/Getty Images)

Roger Federer of Switzerland plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/IAN KINGTON (Photo credit should read IAN KINGTON/AFP/Getty Images)

Roger Federer of Switzerland celebrates a point against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Roger Federer of Switzerland plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Roger Federer of Switzerland plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

Switzerland"s Roger Federer reacts as he plays Russia's Nikolay Davydenko during their ATP World Tour Finals semifinal tennis match at the O2 Arena in London, Saturday Nov. 28, 2009.

Roger Federer of Switzerland gestures as he plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

Roger Federer of Switzerland gestures as he plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

Roger Federer of Switzerland gestures as he plays against Nikolay Davydenko of Russia in a singles semi-final match during the Barclays ATP World Tour Tennis Finals in London, on November 28, 2009. AFP PHOTO/CARL DE SOUZA (Photo credit should read CARL DE SOUZA/AFP/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

Supporters of Switzerland"s Roger Federer in the stands before the start of his semifinal tennis match against Russia's Nikolay Davydenko at the ATP World Tour Finals match at the O2 Arena in London, Saturday Nov. 28, 2009.

LONDON, ENGLAND - 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland serves the ball 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, 2009 in London, England. (Photo by Julian Finney/Getty Images)

LONDON, ENGLAND - NOVEMBER 28: Roger Federer of Switzerland returns the ball 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, 2009 in London, England. (Photo by Clive Brunskill/Getty Images)

Switzerland"s Roger Federer returns to Russia's Nikolay Davydenko during their ATP World Tour Finals semifinal tennis match at the O2 Arena in London, Saturday Nov. 28, 2009.