Novak Djokovic defeats Alexander Zverev to reach Australian Open semi-finals

Novak Djokovic battled to a four-set win over Alexander Zverev (Andy Brownbill/AP)

Novak Djokovic continued his successful battle through the pain barrier with victory over Alexander Zverev to reach the semi-finals of the Australian Open.

The world number one’s hopes of a ninth title in Melbourne Park have hung firmly in the balance since he sustained an abdominal injury during his third-round win against Taylor Fritz.