Novak Djokovic 'extremely lucky' as Lorenzo Musetti forced to retire despite commanding lead

Novak Djokovic has been handed an incredibly lucky reprieve after Lorenzo Musetti had to retire injured despite leading 6-4, 6-3, 1-3 in their Australian Open quarter final.

Djokovic was leading 2-1 in the third set before Musetti took a medical timeout for what appeared to be a hamstring injury.

Two games later on serve, Musetti faulted and looked incredibly ginger before he approached the net, removed his headband and called it quits.

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"Shocking, it's depressing, it sucks is the bottom line," John McEnroe said on Nine.

"That's the best tennis of his life ... you really feel for that young man."

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Post-match, Djokovic conceded to Wally Masur he is "extremely lucky" to get through to the semi final.

"I don't know what to say except that I feel really sorry for him and he was a far better player, I was on my way home tonight," he said.

"These kind of things happen in sport and it's happened to me a few times, but being in quarter of a grand slam and being in full control is so unfortunate.

"I really wish him a speedy recovery. He should have been a winner today, no doubt."

In the first set, Djokovic brought himself undone at times, hitting 18 unforced errors compared to the Italian's eight.

The second set was a similar story with 13 against Djokovic to nine.

Djokovic then took his own brief medical timeout to address an ugly blister on the bottom of his foot and minutes later we had a second timeout with Musetti.

"Talk about the tables turning ... this is an unbelievable turn of events," McEnroe said.

Djokovic then held his serve as Musetti struggled with his movement on the court.

Ultimately a devastating end came for the world No.5 with the quarter-final his best ever result at the AO.

* The following is AI-generated 'What If' analysis that examines the most pivotal points in the match. It was provided courtesy of Infosys

The hollow escape: A king saved by calamity

What if Lorenzo Musetti's body had held up for just one more hour? That is the haunting question that will linger over this quarter-final, far longer than the scoreline will be remembered.

For two sets, the unthinkable wasn't just possible, it was happening. In the opening set, Musetti was not just competing; he was dictating.

He absorbed the pressure of the 24-time major champion and fired it back with interest, sealing the 6-4 opener with a composure that belied his age.

When he unleashed a 162 km/h forehand winner to punctuate that decisive seven-shot rally, he wasn't just taking a set; he was dismantling the aura of invincibility that usually protects Djokovic on Rod Laver Arena.

Had Musetti maintained that physical integrity, the "King of Melbourne" was staring down the barrel of a clean, straight-sets execution. The second set deepened the crisis.

Down 0-1 in sets, Djokovic needed a response, but instead, he found himself drowning in the Italian's brilliance.

The stats paint the picture of a champion besieged: facing a break point in the final game, Djokovic watched a 134.5 km/h return winner scream past him, followed by a set-sealing 140.86 km/h forehand down-the-line that left him stranded.

Trailing 6-4, 6-3, Djokovic wasn't beaten by unforced errors or bad luck; he was being outplayed.

The "what if" here is terrifyingly simple: if the match continues on merit alone, Musetti's relentless court coverage and explosive power likely carry him to the finish line, handing Djokovic his most humbling Australian Open exit in a decade.

Instead, the cruel fragility of sport rewrote the ending. In the third set, just as Djokovic clawed his way to a break lead, Musetti's movement faltered, and the retirement came sudden and sharp.

Djokovic advances, but he walks into the semi finals not as a conqueror, but as a survivor of a storm he didn't quell.

The history books will record a Djokovic victory, but the "truth data" of those first two sets tells a different story: for 90 minutes, the torch had been snatched away, only to be returned by a twist of fate rather than a swing of the racquet.

The champion survives, but the shadow of "what might have been" if Musetti remained standing will loom large over the rest of his campaign.