The World No 1, Jannik Sinner, has pulled out of the Cincinnati Open due to a right knee injury, the Italian announced on Sunday. “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.” The tournament begins on Thursday, the same day as the end of the Masters event in Montreal, which Sinner also missed. Sinner’s subsequent withdrawal from Cincinnati follows that of world No 2 Carlos Alcaraz as the Spaniard continues to battle a wrist injury. The Cincinnati Open and Montreal Masters are the two principal warm-up events ahead of the final grand slam of the season, the US Open, which starts in New York on 30 August.