Stanislas Wawrinka of Switzerland celebrates after defeating Novak Djokovic of Serbia in their quarterfinal at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 21, 2014.(AP Photo/Rick Rycroft)
Stanislas Wawrinka of Switzerland gestures between points as he plays Novak Djokovic of Serbia during their quarterfinal at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 21, 2014.(AP Photo/Rick Rycroft)
Novak Djokovic of Serbia makes a forehand return to Stanislas Wawrinka of Switzerland during their quarterfinal at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 21, 2014.(AP Photo/Rick Rycroft)