World No 1 Jannik Sinner has withdrawn from the China Open, citing his ongoing knee injury that also forced him to miss the US Open. The Italian has not played since winning his second successive Wimbledon title in July, skipping the Canadian Open, Cincinnati Open, and the US Open.

"I'm very sorry to announce that I won't be able to play in Beijing this year," Sinner said on social media. "My knee is not where I would like it to be, and I'm not ready to compete yet, but I will do everything possible to be back on court as soon as I can."

Sinner defeated Learner Tien in straight sets in last year's Beijing final to win his second China Open title. His withdrawal is damaging to his chances of finishing as year-end No 1, with Alexander Zverev already ahead in the Live ATP Race at 8,650 points to Sinner's 7,950.

Sinner aims to recover in time for the Shanghai Masters starting October 7. His absence leaves Novak Djokovic as a headline attraction at the ATP 500 event in Beijing.