Serbian Novak Djokovic waits during his match against Sergiy Stakhovsky (unseen) from Ukraine during the ABN AMRO World Tennis Tournament in Rotterdam, on February 9, 2010. Sergiy Stakhovsk had to quit the match after 54 minutes because of a knee injury. AFP PHOTO ANP KOEN SUYK netherlands out - belgium out (Photo credit should read KOEN SUYK/AFP/Getty Images)

Serbian Novak Djokovic returns the ball in his match against Sergiy Stakhovsky (unseen) from Ukraine during the ABN AMRO World Tennis Tournament in Rotterdam, on February 9, 2010. Sergiy Stakhovsk had to quit the match after 54 minutes because of a knee injury. AFP PHOTO ANP KOEN SUYK netherlands out - belgium out (Photo credit should read KOEN SUYK/AFP/Getty Images)

Serbian tennis player Novak Djokovic leans on his racquet during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne on January 27, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/William WEST (Photo credit should read WILLIAM WEST/AFP/Getty Images)

Serbian tennis player Novak Djokovic gestures during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/Vivek PRAKASH/POOL (Photo credit should read VIVEK PRAKASH/AFP/Getty Images)

Serbian tennis player Novak Djokovic gestures during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/Vivek PRAKASH/POOL (Photo credit should read VIVEK PRAKASH/AFP/Getty Images)

Novak Djokovic of Serbia reacts as he plays Jo-Wilfried Tsonga of France during their five set Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Novak Djokovic of Serbia (L) walks back onto the court after leaving due to illness while playing against Jo-Wilfried Tsonga of France in their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne on January 27, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / PAUL CROCK (Photo credit should read PAUL CROCK/AFP/Getty Images)

Serbian tennis player Novak Djokovic gestures during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/Vivek PRAKASH/POOL (Photo credit should read VIVEK PRAKASH/AFP/Getty Images)

Serbian tennis player Novak Djokovic gestures during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/Vivek PRAKASH/POOL (Photo credit should read VIVEK PRAKASH/AFP/Getty Images)

Novak Djokovic of Serbia (L) shakes hands with Jo-Wilfried Tsonga of France following their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne early on January 28, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / GREG WOOD (Photo credit should read GREG WOOD/AFP/Getty Images)

Serbia's Novak Djokovic touches his stomach prior to leaving the court during his five set Men's singles quarterfinal match against Jo-Wilfried Tsonga of France at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Novak Djokovic of Serbia hits a return during his loss to Jo-Wilfried Tsonga of France in their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne on January 27, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / PAUL CROCK (Photo credit should read PAUL CROCK/AFP/Getty Images)

Serbian tennis player Novak Djokovic watches his racquet as it falls to the ground during his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. Tsonga won 7-6. 6-7. 1-6. 6-3. 6-1. The Australian Open is taking place from January 18-31. AFP PHOTO/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)

Novak Djokovic of Serbia reacts during his loss to Jo-Wilfried Tsonga of France in their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne on January 27, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / PAUL CROCK (Photo credit should read PAUL CROCK/AFP/Getty Images)

Novak Djokovic of Serbia speaks with an official shortly before taking an injury break as he plays Jo-Wilfried Tsonga of France in their Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Serbian tennis player Novak Djokovic (C) walks off court following defeat in his quarter-final men's singles match against French opponent Jo-Wilfried Tsonga on the tenth day of play at the Australian Open tennis tournament in Melbourne early January 28, 2010. The Australian Open is taking place from January 18-31. AFP PHOTO/Torsten BLACKWOOD (Photo credit should read TORSTEN BLACKWOOD/AFP/Getty Images)

Novak Djokovic of Serbia looks dejected during his loss to Jo-Wilfried Tsonga of France in their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne on January 27, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / PAUL CROCK (Photo credit should read PAUL CROCK/AFP/Getty Images)

Supporters wave the Serbian flag as Novak Djokovic of Serbia waves goodbye following his loss to Jo-Wilfried Tsonga of France in their men's singles quarter-final match on day 10 of the Australian Open tennis tournament in Melbourne early on January 28, 2010. Tsonga won 7-6, 6-7, 1-6, 6-3, 6-1 to advance to the semi-final. AFP PHOTO / GREG WOOD (Photo credit should read GREG WOOD/AFP/Getty Images)

Novak Djokovic of Serbia covers his head with a towel during a break as he plays Jo-Wilfried Tsonga of France in their Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia wipes his forehead in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Vivek Prakash-Pool/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia wipes his forehead in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Vivek Prakash-Pool/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia wipes his forehead in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Vivek Prakash-Pool/Getty Images)

Novak Djokovic of Serbia, left, gets a towel from a ball boy as he plays Jo-Wilfried Tsonga of France in their Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Novak Djokovic of Serbia reacts shortly before taking an injury break as he plays Jo-Wilfried Tsonga of France in their Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Novak Djokovic of Serbia leaves the court after losing to Jo-Wilfried Tsonga of France in a Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

Novak Djokovic of Serbia reacts shortly before taking an injury break as he plays Jo-Wilfried Tsonga of France in their Men's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Wednesday Jan. 27, 2010.

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia throws his racquet in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia reacts after a point in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia plays a forehand in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 27: Novak Djokovic of Serbia plays a backhand in his quarterfinal match against Jo-Wilfried Tsonga of France during day ten of the 2010 Australian Open at Melbourne Park on January 27, 2010 in Melbourne, Australia. (Photo by Quinn Rooney/Getty Images)