Lorenzo Musetti explains retiring from Novak Djokovic match as Australian Open star left devastated

"Honestly, I never imagined, you know, the feeling of leading two sets to zero against Novak and playing like that and have the lead of the match like that and be forced to retire is something that, of course, I will never imagine. Of course, it's really painful," Musetti said.

The injury first manifested at the start of the second set, when Musetti noticed something unusual in his right leg.

"I felt there was something strange in my right leg," he continued.

"You know, I continued to play, because I was playing really, really, really well, but I was feeling that the pain was increasing, and the problem was not getting away."

Despite the growing discomfort, Musetti managed to compete through much of the second set, relying heavily on his serve to stay competitive.

However, after receiving a medical timeout early in the third set and sitting for three minutes, the pain intensified dramatically when he attempted to resume play.

Musetti expressed confidence that he has sustained a muscle tear, though he acknowledged he would need medical examinations to confirm the diagnosis.

"I feel personally that I know my body, and I feel personally that I'm kind of secure that this is a tear, unfortunately," he said.

The location of the injury made treatment on court impossible, with the Italian explaining that taping was not an option due to where the problem occurred.

"Well, to tape it, it was a little bit too high, so it was impossible to tape it," Musetti added, noting uncertainty over whether the damage was to his adductor or another muscle.

He confirmed he would undergo comprehensive tests upon returning home.

Djokovic had been struggling badly before Musetti's withdrawal, committing 31 unforced errors across the opening two sets.

The fourth seed admitted afterwards that he had been "on the way home" and told spectators that his opponent deserved to win the match.

Musetti retired with the score at 6-4 6-3 1-3 15-40, walking to the net with his face buried in his hands after shaking his head in disbelief.

The withdrawal marks the tenth mid-match retirement of the Italian's injury-plagued career and his third at a Grand Slam tournament.

There was "no sense and no way" to continue, Musetti said, with the injury preventing him from moving properly or generating power on his serve.

Djokovic, meanwhile, will compete in the semi-finals on Friday.

He remains on course for a 25th Grand Slam title that would move him ahead of Margaret Court in the history books.