Ten-time champion Novak Djokovic has sensationally withdrawn from the Australian Open after losing a marathon first set of his semi-final against second seed Alexander Zverev.

Djokovic walked immediately to the chair umpire to say he could not go on after dropping the set in a tiebreaker after one hour and 21 minutes on Friday.

The former world No.1 again had his left thigh heavily strapped after hurting himself in his quarter-final win over Carlos Alcaraz on Wednesday night.

Djokovic said then he would likely have to skip routine practice before playing Zverev, but declined to reveal the exact details of his injury.

The 37-year-old did, though, say it was of a similar nature to the hamstring injury he nursed while winning his 10th Open title two years ago.  

Zverev’s victory, which came after Djokovic quit after losing the tiebreaker 7-5, propelled the 27-year-old German into his maiden Australian Open final, and third grand slam title match of his career.

The world No.2 lost the 2020 US Open final to Dominic Thiem as well as last year’s French Open decider to Alcaraz.

Zverev will play the winner of Friday night’s second semi-final between Italy’s top-ranked titleholder Jannik Sinner and American world No.20 Ben Shelton.