The stage appeared perfectly set for Jannik Sinner to complete the Career Grand Slam at the 2026 French Open. The Italian arrived in Paris riding a wave of dominance after sweeping all three clay-court Masters 1000 events, while two-time defending champion Carlos Alcaraz pulled out of the Major due to a wrist injury.
However, in one of the biggest shocks of the season, the world No. 1 stunned the tennis community by crashing out of the Major in the second round, undone by a dramatic collapse brought on by physical struggles in the brutal Paris heat.
How the Tennis World Reacted to Jannik Sinner’s Unexpected French Open Loss
Sinner appeared firmly in control at the start of his second-round clash against Juan Manuel Cerúndolo, rushing to a 6-3, 6-2, 5-1 lead. Even though victory was just one game away, he began to show signs of struggle and failed to serve out the match on two occasions. At 5-4 (0-40) in the third set, the Italian brought play to a halt and accepted the option of a medical timeout offered by chair umpire Aurélie Tourte.
Sinner left the court to receive treatment after complaining about dizziness and nausea, and he looked far from his best when he returned. Cerúndolo capitalized on the 24-year-old’s struggles, dominating the remainder of the match to clinch a 3-6, 2-6, 7-5, 6-1, 6-1 victory. In the process, Cerúndolo snapped the world No. 1’s 30-match winning streak and pulled off the biggest upset of the season so far.
Sinner’s unexpected defeat left the tennis community in disbelief. Andre Agassi and Coco Gauff’s former coach, Brad Gilbert, highlighted the sweltering conditions as the 24-year-old’s “kryptonite” and said he was caught off guard by the Italian’s lack of a comeback.
“i’m absolutely stunned that Sin City 🌆 hasn’t found 2nd wind 💨 his kryptonite has gotten to him, Cerundolo Bro’s looks fit as a fiddle and stayed very relaxed 😎,” Gilbert posted.
“absolutely stunning 🤩 Cerundolo shocks Sin City 🌆 wins 18-20 games now top half of draw ✍️ massively wide open to say the least,” he added.
MORE: Why Did Sinner Stop French Open Match Mid-Game? Brutal Conditions and Chair Umpire Exchange
Tennis analyst Blair Henley also called attention to the four-time Grand Slam champion’s struggles in the heat with an amusing meme.
— Blair Henley (@BlairHenley) May 28, 2026
Despite acknowledging the “sad” sight, Serena Williams’ former coach Rennae Stubbs pointed out that she had correctly predicted Sinner’s physical condition would be his biggest threat in Paris.
“As suspected in my substack. The only thing that was going to stop Sinner this tournament was Ian own body! Sad to see but damn, he’s really got to figure that out!” she wrote.
Meanwhile, former French player Gilles Simon took notice of the intriguing turn of events.
“That’s an interesting day!” he posted.
At the same time, tennis journalists José Morgado and Christopher Clarey emphasized the major implications of the shocking loss.
“Huge, huge shock. Cannot believe. Feels like a total different tournament from now on…,” Morgado wrote.
“One of the most closed Grand Slam men’s #tennis tournaments is suddenly one of the most open Zverev, Ruud, Djokovic, Jodar and the list goes on!” Clarey posted.
Following his stunning upset over Jannik Sinner, Juan Manuel Cerúndolo will lock horns with Martín Landaluce in the third round of the French Open. Meanwhile, the world No. 1 has expressed his intention to use his time off to recover mentally before the grass swing, during which he will return to Wimbledon as the defending champion.
