Formidable title favorite Jannik Sinner is out of the French Open in the second round, wasting a chance to serve for the match in the third set before falling to a 3-6, 2-6, 7-5, 6-1, 6-1 loss to 56th-ranked opponent Juan Manuel Cerundolo on Thursday.
Sinner was on a 30-match winning streak stretching back to February, and the odds were overwhelming that he would complete a career Grand Slam by winning the only big title missing in his tennis career -- especially with two-time reigning champion Carlos Alcaraz out with an injured right wrist.
But after leading 5-1 in the third set and potentially a minute away from the locker room, Sinner sensationally lost 18 points in a row to trail 0-40 serving for the match a second time at 5-4. He bent over on the court and walked to his chair.
Sinner was attended to by the medical staff and was allowed to leave the court after saying he felt sick to have his condition assessed and blood pressure taken. When he returned, he lost three more games and the set.
As the match wore on, Sinner bent over on the clay court in apparent exhaustion multiple times and was hardly even running, resorting to drop shots and serve-and-volley tactics to try to shorten the points.
"Woke up this morning, didn't feel very well and tried to keep the points very short," Sinner said. "Also in the beginning I was hitting very clean, very good, and then I just kind of hit the wall, and that's it."
He later added, "I don't remember last time I felt this weak."
Sinner attempted to cool himself with a handheld fan on changeovers and put bags of ice around his neck but ultimately dropped 18 of the last 20 games. He became the first men's No. 1 seed to lose in the second round or earlier since Andre Agassi in 2000.
"I feel sorry for him because he deserved to win a lot of matches, and of course he was deserving to win this match, but then I don't know what happened," Cerundolo said in his on-court interview.
The temperature at the start of the match was 84 degrees Fahrenheit and then rose to 90.
"It was warm but not crazy warm," Sinner said. "I feel like it was quite OK to play. Really it was nothing against the heat, nothing against the weather. It was just me today, but it happens."
The heat has taken its toll on other players, with Casper Ruud saying he felt like a "zombie" during his first-round match, while Czech player Jakub Mensik collapsed at the end of a five-set battle Wednesday.
Sinner struggled in the heat at the Australian Open against Eliot Spizzirri in January. The roof was closed, and the third-round match swung his way.
As the top seed in last year's French Open final, Sinner squandered a two-set lead and three match points as Alcaraz claimed the title.
Sinner's loss Thursday leaves Novak Djokovic as the only men's player left at the French Open to have claimed a Grand Slam title. It also means, for the first time since Djokovic's US Open win in 2023, a major crown will be claimed by someone other than Sinner or Carlos Alcaraz.
Cerundolo was a 32-1 underdog to win Thursday's match at DraftKings Sportsbook, with the live odds getting as long as 100-1. Sinner had been a -50000 favorite to win.
Before the tournament, Sinner was a -300 favorite to win the title, the second-shortest pretournament odds at a Grand Slam since at least 1990 and the shortest since Rafael Nadal (-400) at the 2009 French Open, where Nadal was upset in the fourth round.
As Sinner now turns his focus to Wimbledon, he said he didn't plan to play any lead-in events on grass and would focus on recovery. Wimbledon begins June 29.
Cerundolo's brother, Francisco, also advanced to the third round Thursday with a 2-6, 6-4, 6-2, 6-1 win over Hugo Gaston.
No. 10 Flavio Cobolli and No. 18 Learner Tien moved on as well, while No. 16 Valentin Vacherot withdrew with a foot injury. Frenchman Moise Kouame, 17, became the youngest man to reach the third round of a Grand Slam since Nadal was also 17 at 2003 Wimbledon after beating Adolfo Daniel Vallejo 6-3, 5-7, 3-6, 2-6, 7-6 (8).
ESPN's D'Arcy Maine and Doug Greenberg, The Associated Press and PA contributed to this report.