Serena Williams sister Venus Williams United States during the final of the Womens Doubles AOTC

Serena Williams of the United States, left, and her sister Venus Williams prepare to receive serve from Cara Black of Zimbabwe and Liezel Huber of the United States during the final of the Women's Doubles at the Australian Open tennis championship in Melbourne

Serena Williams of the US Women's singles semifinal AOTC in Melbourne

Serena Williams of the United States returns to Li Na of China in their Women's singles semifinal match at the Australian Open tennis championshipt in Melbourne, Australia

Serena Williams of the U.S. reacts during her quarter-final match against Victoria Azarenka of Belarus at the Australian Open tennis championshipt in Melbourne

Serena Williams of the USA serves to Samantha Stosur

Serena Williams of the USA serves to Samantha Stosur of Australia in their round four match at the Australian Open tennis tournament in Melbourne, Australia

Serena Williams of the United States returns to Victoria Azarenka of Belarus during their Women's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia.

Venus Williams of the United States reacts after losing a point to Li Na of China during their Women's singles quarterfinal match at the Australian Open tennis championship in Melbourne, Australia

Serena And Venus Williams of the United States celebrate

Serena (L) and Venus Williams of the United States celebrate after defeating Andrea Hlavackova and Lucie Hradecka of the Czech Republic at their women's doubles third round match at the Australian Open Tennis Tournament in Melbourne, Australia

Serena Williams of the United States serves to Petra Kvitova

Serena Williams of the United States serves to Petra Kvitova of Czech Republic during their Women's singles match at the Australian Open tennis championship in Melbourne, Australia.

Britain Prince William with Serena Williams of the US and her mother Oracene Price

Britain's Prince William (C) posing with Serena Williams (R) of the US and her mother Oracene Price (L) at the Australian Open tennis tournament in Melbourne, Australia

Serena Williams at the Australian Open tennis championship

Serena Williams of the United States reacts during an exhibition tennis match in Melbourne, Australia.

Roger Federer of Switzerland, left, and Serena Williams of the United States celebrate a point during an exhibition tennis match in Melbourne, Australia

Serena Williams of the United States returns the ball to Poland's Urszula Radwanska during their Women's first round singles match at the Australian Open tennis championship in Melbourne, Australia.

Serena Williams of the United States looks to return the ball to Poland's Urszula Radwanska during their Women's first round singles match at the Australian Open tennis championship in Melbourne, Australia.

Serena Williams at the Sydney International tennis tournament

American Serena Williams plays a shot in her match against Maria Jose Martinez Sanchez of Spain at the Sydney International tennis tournament in Sydney, Australia