Andy Roddick didn't think it was fair for Novak Djokovic to receive boos from the Australian Open as the American highlighted it wouldn't be right at all it was the last memory of the Serb at Melbourne Park.

Djokovic sustained a muscle tear in his upper left leg during his quarter-final victory over Carlos Alcaraz on Tuesday and admitted he did not have anything left in the tank after attempting to play through the pain.

Novak Djokovic retired mid-game during his semi-final clash with Alexander Zverev, who'll now face world No.1 Jannik Sinner in the Australian Open final on Sunday