Maria Sharapova of Russia celebrates winning match point against Angelique Kerber of Germany in their third round women's singles match on day six of the 2012 Australian Open. Sharapova won 6-1, 6-2. – AFP Photo.

Novak Djokovic of Serbia hits a shot against Nicolas Mahut of France in their third round men's singles match on day six of the 2012 Australian Open. Djokovic won 6-0, 6-1, 6-1. – AFP Photo.

Juan Ignacio Chela of Argentina plays a stroke during his men's singles match against David Ferrer of Spain on the sixth day of the Australian Open. Ferrer won 7-5. 6-2. 6-1. – AFP Photo.

A spectator with her face painted with the Chinese flag watches Julien Bennetteau of France play Kei Nishikori of Japan in their third round men's singles match on day six of the 2012 Australian Open. – AFP Photo.

Petra Kvitova of the Czech Republic waits in her chair as her opponent Russia's Maria Kirilenko has a medical time out during their third round match at the Australian Open. – AP Photo.

China's Zheng Jie makes a backhand return to Italy's Roberta Vinci during their second round match at the Australian Open. – AP Photo.

Serena Williams of the United States celebrates after winning over Hungary's Greta Arn during their third round match at the Australian Open. – AP Photo.

Kei Nishikori of Japan hits a return to Julien Benneteau of France during their men's singles match at the Australian Open. – Reuters Photo.

Fans hold signs during the men's singles match between Kei Nishikori of Japan and Julien Benneteau of France at the Australian Open tennis tournament in Melbourne January 21, 2012. The signs read, "Attack" (L) and "Nishikori". – Reuters Photo.

Andy Murray of Britain tumbles over on the court during his match with Michael Llodra of France at the Australian Open. – Reuters Photo.

Milos Raonic of Canada hits a return to Lleyton Hewitt of Australia during their men's singles match at the Australian Open. – Reuters Photo.

Lleyton Hewitt of Australia celebrates winning the second set of his men's singles match against Milos Raonic of Canada at the Australian Open. – Reuters Photo.