World No. 1 tennis player Jannik Sinner produced one of the worst betting defeats in sports history on Thursday, losing a French Open match he was a -50,000 live favorite to win.
Sinner was up by two sets and 5-1 in the third over Juan Manuel Cerúndolo, a +3,300 pre-match underdog.
Key Takeaways
- Sinner appeared to struggle with cramps amid the heat wave in Europe.
- One user lost $55,000 supporting Sinner for a possible gain of less than $1,000.
- Cerúndolo is still a +25,000 underdog to win the French Open, despite the win.
Sinner's -300 pre-tournament odds made him the largest favorite at any Grand Slam competition since Rafael Nadal at the 2009 French Open.
After surging ahead to a dominant lead, Sinner appeared to struggle with the 90-degree weather and real feel of around 95, which is even hotter on the clay courts. Cramping and a loss of energy plagued him as he lost control of the match. Cerúndolo went on to win 3-6, 2-6, 7-5, 6-1, 6-1.
Sinner’s -25,000 pre-match odds gave him a 99.6% implied probability of winning the match, according to theScore Bet. His -50,000 live odds increased that number to 99.8%, meaning that he would be mathematically expected to lose the match once every 500 times in that circumstance.
Jannik Sinner ended up losing this 😳🤯
— theScore Bet (@theScoreBet) May 28, 2026
The World No. 1 was -25000 pregame. Cerundolo entered at +3300. pic.twitter.com/fcOGcXNgzu
The second-round elimination is the worst of Sinner’s career since, fittingly, the 2023 French Open.
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Huge wins and losses
One online bettor shared images of a $50,000 contract purchased at Kalshi and a $5,000 wager placed at FanDuel, both of which required Sinner to win the match. The full possible payout was a total of $999.07, or 1.8% of the stake.
Instead of walking out with an extra thousand bucks, the user lost all $55,000 in Sinner’s collapse to the 24-year-old Cerúndolo.
If you saw $999.07 on the ground, you’d pick it up, right? Jannik Sinner🔐
— Foazn (@FoaznPoker) May 28, 2026
Couple things:
•Sinner is GUARANTEED to win
•Foazn won’t wake up at 5am to watch
I make money in my sleep; you wake up to make money #levels pic.twitter.com/SRG1Ux66iW
On the other side, a Polymarket trader walked away with $21,999 after backing the underdog. The 2% probability at purchase resulted in the user winning more than 44 times their stake.
🚨JUST IN: Someone turned $500 into $22,000 at the French Open
— Polymarket Sports (@PolymarketSport) May 28, 2026
A trader bought Juan Cerundolo at 2% to beat 1 seed Jannik Sinner
Sinner lost in 5 sets after dealing with severe cramps pic.twitter.com/xk3qlNbu1y
More than $14 million in contracts were traded for the Sinner-Cerúndolo match at prediction market leader Kalshi. Another $4 million in trading activity was reported just for the outright winner market at Polymarket.
Updated French Open odds
With Sinner now out of the tournament, world No. 3 Alexander Zverev is a +190 favorite to win the French Open at FanDuel Sportsbook. He has been to three finals but never won a Grand Slam tournament in his career.
Novak Djokovic's odds have him second at +400, followed by Norwegian Casper Ruud (+900) and Spaniard Rafael Jodar (+1,000).
Despite beating Sinner and progressing past the second round for the first time in his Grand Slam career, Cerúndolo is still at just +25,000 in French Open odds. His countryman, Francisco Cerúndolo, is fifth at +1,500.
