Jannik Sinner stood one game away from a routine win. He had won the first two sets easily, 6-3 and 6-2, and now led the third by 5-1 against a man ranked 56th in the world. On the red clay of Court Philippe-Chatrier, the World No. 1 looked unbeatable.
Then his body began to fail him.
The 24-year-old Italian lost to Argentina's Juan Manuel Cerúndolo, 3-6, 2-6, 7-5, 6-1, 6-1, in one of the biggest upsets in French Open history. Cerúndolo recovered from two sets down to take the final three sets.
The heat played its part. Temperatures at Roland-Garros climbed to 29-32 degrees Celsius, and as Sinner tried to serve out the match, cramping set in. He took a medical timeout but was immediately broken. He lost the third set 7-5, then the match unraveled completely. Cerúndolo, a clay-court specialist, won 18 of the final 20 games.
Sinner had arrived as the overwhelming favorite with a 30-match winning streak and three spring Masters titles. He is a four-time Grand Slam champion. None of it mattered once the cramps took hold.
Cerúndolo reached the third round of a major for the first time. His older brother Francisco is also an ATP player, but the younger Cerúndolo had now done something his brother never has.
For Sinner, the loss stings deeply. Roland-Garros is the only major he has never won. He was the runner-up last year. With defending champion Carlos Alcaraz injured, the path to a first French Open title had rarely seemed clearer. Instead, the favorite was gone before the third round, a single game away from victory.