John McEnroe and John Millman say the crowd's reaction to Novak Djokovic's decision to quit his semi was 'disrespectful'.

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.

Jim Courier and John Millman unpack what Novak Djokovic's future in the sport holds after his sudden retirement at the Australian Open.

Jim Courier and John Millman unpack what Novak Djokovic's future in the sport holds after his sudden retirement at the Australian Open.

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.

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

It’s safe to say Novak Djokovic’s relationship with the Australian Open crowd hasn’t always been perfect.

It’s safe to say Novak Djokovic’s relationship with the Australian Open crowd hasn’t always been perfect.