Serbia's Novak Djokovic hits a forehand return to Tomas Berdych of the Czech Republic during their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 22, 2013. (AP Photo/Aaron Favila)

Associated Press
Serbia's Novak Djokovic hits a forehand return to Tomas Berdych of the Czech Republic during their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 22, 2013. (AP Photo/Aaron Favila)
Serbia's Novak Djokovic hits a forehand return to Tomas Berdych of the Czech Republic during their quarterfinal match at the Australian Open tennis championship in Melbourne, Australia, Tuesday, Jan. 22, 2013. (AP Photo/Aaron Favila)