During the third set, Alcaraz destroyed his racket by repeatedly smashing it on the court in a rare show of frustration for the four-time Grand Slam winner.

The No. 3 player in the ATP rankings lost 4-6, 7-6 (7-5), 6-4 to the 37-year-old Monfils.

Posting in Spanish on X on Saturday, Alcaraz said his attitude was not correct, and his actions should not have been done on the court.

The 21-year-old added that it's difficult to control yourself when your heart rate is high, and he will work to ensure it doesn't happen again.

Alcaraz was playing his first match since earning a silver medal at the Paris Olympics after losing to Novak Djokovic, who also beat him last year in the Cincinnati final.

“I felt like it was the worst match that I've ever played on my career,” Alcaraz said Friday. “I've been practicing really well. I was feeling great. But I couldn't play. I want to forget it and try to move on to New York.”

The U.S. Open begins in New York on August 26.