French Open 2026 results: World No. 1 Jannik Sinner stunned in second round upset by Juan Manuel Cerundolo

Unseeded Argentinian Juan Manuel Cerundolo notched the biggest win of his career in the second round of Thursday's French Open, stunning World No. 1 Jannik Sinner in five sets, 3-6, 2-6, 7-5, 6-1, 6-1.

Cerundolo won 15 consecutive points in the third set to force a fourth, leading to Sinner struggling with his fitness in the final two sets. At one point in the third set, Sinner led 5-1 before asking to speak with the umpire for a dehydration-related timeout. 

The umpire allowed a medical timeout and granted Sinner to briefly leave the court.  

During the TNT broadcast, commentator Jim Courier scorched the umpire for allowing Sinner's timeout. Players are usually not allowed to take a medical timeout due to cramping, which is what Sinner asked for after noticeably moving slower in the third set.

"That's not fair. That's not right," Courier said. "We love the top players, they drive the sport, but you've gotta apply the rules fairly. The rules are being bent for the top players."

Earlier this year against Daniil Medvedev at the 2026 Italian Open, Sinner began struggling with cramping before he asked for a timeout. Medvedev slammed the move after the loss and said the tour is giving preferential treatment to its top players.

It was Sinner's first loss on tour since February, snapping a 30-match winning streak. He was looking to complete the career Grand Slam and entered the tournament as a near -300 favorite to do so, thanks in part to his rival, Carlos Alcaraz, missing the event with injury.

The 24-year-old Cerundolo is into the third round of a grand slam for the first time in his career, doing so in improbable fashion after struggling in the first two sets before winning the endurance war against the four-time majors champion. Cerundolo's victory opens the field for other frontrunners, including Novak Djokovic, who is gunning for his record-extending 25th grand slam.

This will be the first non Alcaraz-Sinner major winner since Djokovic in 2023. Sinner's streak of nine consecutive finals appearances is over.

Cerundolo pressed the issue throughout the final two sets, taking advantage of Sinner's slowing body with pounding winners and an array of nice returns. From four points away from losing in the third to moving on to the weekend of a major for the first time in his career, Cerundolo can now prep for his next match after a tidy three-hour and 35-minute five-setter after taking down a titan.