Jannik Sinner crashed out of the French Open in the second round, suffering from illness in the sweltering Roland-Garros heat as he lost to Juan Manuel Cerundolo from two sets and 5-1 up.

Sinner looked to be cruising into the third round with another straight-sets victory, but, one day after severe conditions caused Jakub Mensik to collapse on court following a win over Mariano Navone, they also appeared to take their toll on the world number one as he slumped to a 3-6 2-6 7-5 6-1 6-1 defeat.

After Cerundolo held serve to stay in the match at 5-1 in the third set, Sinner had an opportunity to finish things with the ball in hand.

But instead, his run of 25 consecutive holds was brought to an end as he repeatedly signalled that his legs were cramping up and he was close to vomiting. 

Sinner opted for a chair umpire consultation and left the court for seven minutes, but that pause did nothing to change the momentum as Cerundolo took four straight games to love, with his opponent barely chasing after any shots placed either side of him.

One close line call frustrated Sinner as he narrowly avoided taking the third set to a tie-break, but the cost of his exertions was clear as another stoppage preceded the fourth set. 

A hold in his opening service game was the only game Sinner won as Cerundolo swiftly took that set, and the four-time grand slam champion was unable to recover physically for the decider.

Cerundolo stormed into a 4-0 lead, and though Sinner dug deep to hold in game five and carved out two break points in game six, he was unable to convert, with his usual speed to the net deserting him as Cerundolo moved within one game of victory.

And another break to love sealed the deal, with Sinner far off his usual pace as Cerundolo swept a left-handed forehand across the court to convert his first match point. 

Data Debrief: Sinner and Alcaraz stranglehold broken

For the first time since the 2023 US Open, where Novak Djokovic claimed his 24th major crown, the men's singles title at a grand slam will be won by someone other than Sinner or Carlos Alcaraz.

The duo had split the last nine major titles between them, with Sinner taking four and Alcaraz claiming five. But fitness issues hampered the former on Thursday, after a wrist injury prevented the latter from even attempting to participate in Paris. 

Cerundolo admitted in his post-match interview that he was fortunate to encounter a below-par Sinner, but the world number 54 became the lowest-ranked player to defeat the world number one at Roland-Garros since Ramon Delgado (97) versus Pete Sampras in 1998.

And in the last 20 years, Sinner is only the second top seed to lose in the round of 64 of a grand slam men's singles draw, after Rafael Nadal at the 2023 Australian Open.