Sloane Stephens of the United States reacts after defeating compatriot Serena Williams in their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, on Wednesday, Jan. 23, 2013. (AP Photo/Andy Wong)

Photo by: Andy Wong

Sloane Stephens of the United States reacts after defeating compatriot Serena Williams in their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, on Wednesday, Jan. 23, 2013. (AP Photo/Andy Wong)