Sometimes a sure thing is a disaster. 

A BetMGM sports gambler experienced the bad beat of a lifetime after they lost $25,000 betting on Carlos Alcaraz to win his second-round match against Botic van de Zandschulp of the Netherlands in the U.S. Open on Thursday. 

Alcaraz, the No. 3 ranked player in the world, was a -10,000 favorite to take down van de Zandschulp, whom he had beaten in straight sets in each of their past two matchups. 

The wager would’ve won the bettor a meager $250 had Alcaraz prevailed. 

Pre-tournament, Alcaraz was +165 at ESPN BET to win it ahead of Novak Djokovic and Jannik Sinner, who were both +240. 

Alcaraz was vying for his fourth career and third straight Grand Slam title. 

“I don’t know what to say right now. I mean, first of all, I think he played great,” Alcaraz said after the match. “I thought he was going to give me more points. He didn’t make a lot of mistakes that I thought he was going to [make]. So I was confused a little bit. I didn’t know how to manage that, how to deal with it. I couldn’t increase my level.”

Van de Zandschulp, 28, is ranked No. 78 in the world and previously reached as high as No. 22 in August 2022. 

Alcaraz, 21, was coming off an Olympic silver medal win after falling to Djokovic in the gold medal showdown earlier this month.

The Spaniard won the French Open in June and added a Wimbledon title a month later before his rough showing in Queens.

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Djokovic is now a +140 favorite to win the tournament at BetMGM. 

He’s closely trailed by Sinner at +175. 

Alexander Zverev (+450) and Daniil Medvedev (+750) are the only other players with odds better than 25/1.