Seemingly moments away from being able to retreat to the locker room with another win under his belt, Sinner's second-round match descended into a dizzy nightmare on Thursday as heatstroke at 33C melted his superman powers and the world No.1 bowed out 3-6 2-6 7-5 6-1 6-1 to world No.56 Juan Manuel Cerundolo.
It felt like a seismic shock for the sport, but unbackable favourite Sinner, foiled in his odds-on shot at completing his career grand slam, shrugged it off, saying that though it was "tough to take", he was making no excuses for his hot-weather vulnerability that also afflicted him in the Australian Open.
"It was warm, but it was okay. It was not like I was dying because of the heat. This can happen," he reasoned. "I feel it was okay to play. Nothing against the weather - it was just me today."
He reckoned he hadn't been feeling well in the morning after not getting much sleep, and put his woeful day down to a host of issues, including his recent heavy programme and the limited recovery time after a late-night finish to his first-round match.
But no-one could foresee the extraordinary drama as Sinner served for the match at 5-4 in the third after he'd already been "starting to feel very dizzy, very low of energy" from the middle of that stanza during which he lost 15 points in a row. He reckoned he'd never felt as weak.
And at 0-40 down, he really "hit the wall", slumping on to the courtside advertising hoardings on Court Philippe Chatrier briefly, prompting umpire Aurelie Tourte to allow him to leave court for five minutes.
That decision was controversial enough, with Jim Courier among those who felt he shouldn't have been allowed a medical timeout because heat-related cramp was a conditioning issue. Sinner got "unbelievably lucky", said the four-time grand slam champ.
But not lucky enough. In Melbourne, he'd also struggled in even hotter conditions against Eliot Spizzirri. Then the heat rules kicked in, he had time to recover as the roof on Rod Laver Arena was closed, and then returned to go on to the semis.
Here, though, there was no escape, as he returned to lose 16 of the last 18 games, after he'd won 16 of the first 21. He effectively threw away the fourth set, hoping to drag up one last monumental effort in the fifth. It didn't work.
The sports world was stunned as the 24-year-old had been the most dominant favourite to win any grand slam since Rafa Nadal in his pomp at Roland Garros, unbeaten in 30 matches and no defending champion Carlos Alcaraz to threaten him, the Spaniard being sidelined by a wrist injury.
Now, though, after nine successive grand slams won by Sinner and Alcaraz, the greatest slam duopoly in tennis annals has been ended, with the door potentially opened for Novak Djokovic, who beat Sinner in Melbourne, to now win that record 25th major title.
Djokovic was the last to win a major before the dominant duo at the 2023 US Open, but now everyone will be dreaming, including Alex de Minaur who could face the Serb in the quarter-final.
Yet Sinner and his team, co-headed by Aussie super-coach Darren Cahill, are determined it'll be just a blip. "It's tough to accept, of course, but now I have a lot of time to recover."
He said he probably wouldn't play any tournament on grass before Wimbledon. "I need really some time off, recover completely, also mentally, and then be ready to go again for Wimby.
"I always try to look the positive side. Played really good, winning three tournaments in a row on clay, hitting the ball in a good way, moving well -- and today was just not meant to be."
