An injured Novak Djokovic quit because of a torn muscle in his left leg after dropping the first set of his Australian Open semifinal against Alexander Zverev on Friday. Djokovic lost the opener 7-6 (5) in a tiebreaker and immediately walked around the net to concede the match to Zverev.

Novak Djokovic is out of the Australian Open in stunning fashion. The 24-time slam champion medically retired immediately after dropping the first set of his semifinal match against No. 2 Alexander Zverev in a tiebreak 7-6 (5).

Alexander Zverev chided the crowd after they booed Novak Djokovic for retiring due to injury after the first set in an Australian Open semifinal.