Ana Ivanovic of Serbia celebrates a point won against Serena Williams of the U.S. during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014. (AP Photo/Aaron Favila)
Serena Williams of the U.S. supports herself with a racket as she plays Ana Ivanovic of Serbia during their fourth round match at the Australian Open tennis championship in Melbourne, Australia, Sunday, Jan. 19, 2014.(AP Photo/Aaron Favila)