In a stunning development at the Australian Open, Novak Djokovic withdrew because of injury after losing the first set of his semifinal match versus Alexander Zverev. Zverev, the No. 2 seed, won a grueling first set in a 7–6 tiebreaker that lasted one hour and 26 minutes.

Novak Djokovic's semifinal match vs. Alexander Zverev at the Australian Open ended far sooner than the Serbian tennis star—or the paying public—would have liked on Friday afternoon at Rod Laver Arena in Melbourne.

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).