Bob and Mike Bryan of the US celebrate after defeating Robin Haase and Igor Sijsling of the Netherlands in the men's doubles final at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 27, 2013. (AP Photo/Andrew Brownbill)
Bob and Mike Bryan of the US celebrate after defeating Robin Haase and Igor Sijsling of the Netherlands in the men's doubles final at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 27, 2013. (AP Photo/Andrew Brownbill)
Victoria Azarenka of Belarus waves to the crowd after winning her semifinal match against Sloane Stephens of the US at the Australian Open tennis championship in Melbourne, Australia, Thursday, Jan. 24, 2013. (AP Photo/Andrew Brownbill)
Victoria Azarenka of Belarus waves to the crowd after winning her semifinal match against Sloane Stephens of the US at the Australian Open tennis championship in Melbourne, Australia, Thursday, Jan. 24, 2013. (AP Photo/Andrew Brownbill)
Serbia's Novak Djokovic hits a forehand return to France's Paul-Henri Mathieu during their first round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 14, 2013. (AP Photo/Andrew Brownbill)
Serbia's Novak Djokovic hits a forehand return to France's Paul-Henri Mathieu during their first round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 14, 2013. (AP Photo/Andrew Brownbill)
Novak Djokovic of Serbia celebrates after defeating Andy Murray of Britain during their semifinal at the Australian Open, in Melbourne, Australia, early Saturday, Jan. 28, 2012. (AP Photo/Andrew Brownbill)
Serena Williams of the U.S. reacts in frustration during her fourth-round match against Russia's Ekaterina Makarova at the Australian Open in Melbourne, Australia, on Monday, Jan. 23, 2012. (AP Photo/Andrew Brownbill)
Serena Williams celebrates after defeating Greta Arn during their third-round match at the Australian Open, in Melbourne, Australia, Saturday, Jan. 21, 2012. (AP Photo/Andrew Brownbill)
