A leading tennis expert had pinpointed the benefits that Novak Djokovic was enjoying with Andy Murray as his coach before his shock retirement from the Australian Open on Friday. Djokovic called it quits after dropping the first set against Alexander Zverev,

Djokovic retired hurt in his Australian Open semi-final against Daniil Medvedev after struggling with a muscle tear in his upper leg, having been in obvious discomfort throughout the opening set.

Novak Djokovic had Andy Murray in his corner throughout the Australian Open before his run ended in the semi-final - ending his hopes of making more history in Melbourne