Sloane Stephens of the U.S. makes a forehand return to Victoria Azarenka of Belarus during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014. (AP Photo/Aaron Favila)
Victoria Azarenka of Belarus celebrates after her fourth round win over Sloane Stephens of the U.S. at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Eugene Hoshiko)
Victoria Azarenka of Belarus celebrates after defeating Sloane Stephens of the U.S. in their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Aaron Favila)
Victoria Azarenka of Belarus celebrates after defeating Sloane Stephens of the U.S. in their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Aaron Favila)
Sloane Stephens of the U.S. serves to Victoria Azarenka of Belarus during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Eugene Hoshiko)
Victoria Azarenka of Belarus makes a backhand return to Sloane Stephens of the U.S. during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Monday, Jan. 20, 2014.(AP Photo/Aaron Favila)