Maria Sharapova of Russia takes a drink during a practice session ahead of the Australian Open tennis championship in Melbourne Australia, Sunday, Jan. 12, 2014. (AP Photo/Aaron Favila)
Maria Sharapova of Russia prepares to make a backhand return during a practice session ahead of the Australian Open tennis championship in Melbourne Australia, Sunday, Jan. 12, 2014. (AP Photo/Aaron Favila)
Serena Williams of the United States speaks during a press conference ahead of the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 11, 2014. (AP Photo/Aaron Favila)
Victoria Azarenka of Belarus speaks during a press conference at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 12, 2014. (AP Photo/Shuji Kajiyama)
Victoria Azarenka of Belarus speaks during a press conference at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 12, 2014. (AP Photo/Shuji Kajiyama)
Bernard Tomic of Australia hits a forehand to Juan Martin del Potro of Argentina during the final of the Sydney International tennis tournament in Sydney, Australia, Saturday, Jan. 11, 2014. (AP Photo/Daniel Munoz)
Japan's Kei Nishikori makes a backhand return to Tomas Berdych of the Czech Republic in their final match of the Kooyong Classic ahead of the Australian Open tennis championship in Melbourne, Australia, Saturday, Jan. 11, 2014. (AP Photo/Aijaz Rahi)