Ash Barty gives her take on Novak Djokovic quitting his Australian Open semi final and the crowd's reaction to him.

Ash Barty gives her take on Novak Djokovic quitting his Australian Open semi final and the crowd's reaction to him.

John McEnroe gives his immediate reaction to Novak Djokovic's semi final retirement.

John McEnroe gives his immediate reaction to Novak Djokovic's semi final retirement.

Ten-time champion Novak Djokovic may have played his last Australian Open after quitting his semi-final injured, sending Alexander Zverev into the...

MELBOURNE, Australia (AP) — Spectators booed an injured Novak Djokovic as he left the court in Rod Laver Arena after quitting one set into his...

MELBOURNE, Australia (AP) — Spectators booed an injured Novak Djokovic as he left the court in Rod Laver Arena after quitting one set into his...

MELBOURNE, Australia (AP) — Spectators booed an injured Novak Djokovic as he left the court in Rod Laver Arena after quitting one set into his...

MELBOURNE, Australia (AP) — Spectators booed an injured Novak Djokovic as he left the court in Rod Laver Arena after quitting one set into his...

Spectators booed an injured Novak Djokovic as he left the court in Rod Laver Arena after quitting one set into his Australian Open semifinal against...