Sinner's knee has kept him out of Beijing. Two titles in a row could make Zverev world No. 1

Jannik Sinner will not defend his China Open title. The world No. 1 withdrew from Beijing on Friday 25 September in a video on X, saying his knee was not yet where he wanted it to be and that he was not ready to compete. He gave no date for his return.

It is the fourth tournament he has missed since he beat Alexander Zverev in the Wimbledon final on 12 July. The right knee problem had already kept him out of Canada, Cincinnati and the US Open, where Zverev won his second major of the year.

Zverev is the top seed in Beijing. He began on Thursday by beating Cameron Norrie 7-6, 6-4, after saving a set point in the first set, and that keeps one specific route to the top of the rankings open.

After the US Open, the ATP put the gap between the two at 1,810 points. Sinner's 500 points from winning Beijing last year now come off his total. Zverev loses the 100 he earned by reaching the quarter-finals, but 40 points from this year's United Cup return to his count in their place. That leaves the gap at 1,370.

If Zverev wins Beijing, the title is worth 500 points and replaces the United Cup result, which cuts the gap to 910. Both men lost in the third round in Shanghai last year, so each drops 50 points there. If Sinner does not play in Shanghai and Zverev wins it, the German finishes 90 points ahead. He would be No. 1 in the rankings published on Monday 19 October, the day after the final.

He needs both titles. Reaching the Beijing final and then winning Shanghai would still leave him 80 points short. If Sinner does play in Shanghai, reaching the last 16 would be enough to keep him at No. 1 even if Zverev wins both events.

Zverev would become the 30th player in the history of the ATP Rankings to reach No. 1. He has won neither event. He is a three-time semi-finalist in Beijing, and his best Shanghai result is the 2019 final, which he lost to Daniil Medvedev.

Whether Sinner plays in Shanghai, which runs from 7 to 18 October, is not settled. Corriere dello Sport reported on 25 September that he could also miss it and stay in Monte Carlo to train for the European events. Sky Sport Italia reported the same evening that Shanghai remained his target, with his participation still not certain. Sinner has not said what the problem with his knee is.

The pressure does not end in October either. Sinner has 3,000 more points to defend from his titles in Vienna, Paris and the ATP Finals, against 930 for Zverev. Both are entered in Vienna, which starts on 24 October. Zverev has also led the Race to Turin, which counts only this season's results, since his US Open win. He has kept his form since New York, clinching the Laver Cup for Team Europe last weekend.