World number one Jannik Sinner has pulled out of the Cincinnati Open with a right knee injury, tournament organisers said on Sunday, handing the ‌Italian a blow in his preparations for this month’s U.S. Open.

The 24-year-old Italian, who claimed his fifth Grand Slam title  at Wimbledon last month, had also pulled out of the Canadian Open, a key warm-up event for ⁠the U.S. Open.

Sinner won the Cincinnati title in 2024 and finished runner-up to seven-times Grand Slam champion Carlos Alcaraz there last year.

“After consulting with my doctors and my team, I have to announce that I need to withdraw from the Masters 1000 tournament in Cincinnati,” Sinner said in a statement.

“My right knee has been bothering me and ‌even ⁠though we have been working hard with my medical team, I have to accept that I’m not ready to compete yet.

“I’m very disappointed not to be able to play in ⁠Cincinnati… I can’t wait to be back next year and I’m now focusing on getting ready for the U.S. Open.”

Sinner’s withdrawal further ⁠depletes the field in Cincinnati, with U.S. Open champion Alcaraz also sidelined by a wrist injury.

The Cincinnati Open main ⁠draw begins on August 13, while the U.S. Open main draw gets under way on August 30.