Jannik Sinner has been told that any setback in his current knee problem could bring his 2026 season to an early close, with one Italian voice warning that the situation should act as a lesson to the rest of the tour.

On Friday, Sinner confirmed he would miss the season’s final Grand Slam because of an ongoing “right knee issue”. The announcement came only five weeks after he successfully defended his Wimbledon title, defeating Alexander Zverev in four sets.

Given his 44-3 record, he would have entered the New York event as a leading contender. Yet his latest withdrawal also follows the physical problem that ended his French Open hopes in Paris. There, after moving to a commanding lead against Juan Manuel Cerundolo, he eventually lost in five sets.

Before that setback, Sinner had made history by becoming the first man to win the first five Masters 1000 events of the season. He was also only the second man to sweep all three clay Masters 1000 tournaments, following Rafael Nadal in 2010 before Nadal went on to win the French Open.

Former world No 12 and commentator Paolo Bertolucci gave a frank assessment of the situation.

“Undoubtedly, the grind Sinner put in this year, which led to winning 5 consecutive Masters 1000s, from Indian Wells to Rome via Miami, Monte Carlo, and Madrid, must have left some aftereffects,” he said in an interview with La Gazzetta dello Sport.

He added: “You can’t show up at this level if the previous issue hasn’t been resolved. A potential relapse, in fact, would be disastrous and could even lead to an early end to the 2026 season.

“So, you have to tread carefully, do the right things, not let yourself be driven by the anxiety to return at all costs.

“There’s a very fine line that absolutely must not be crossed. It costs Sinner and his team a lot to say no to the US Open, but it’s a no that comes at the end of a precise journey.”

Sinner has played nine tournaments this season and remains top of the Live ATP Rankings on 12,800 points, a total that will drop to 11,500 after the US Open. Zverev, currently 3810 points behind, cannot overtake him even if he wins his first US Open title.

Bertolucci said the case should be taken as a wider warning about scheduling, arguing that players cannot keep pushing week after week simply because results are going well.

Sinner is expected to return at the Beijing Open, scheduled for September 30 to October 6.

Carlos Alcaraz and Serena Williams have been granted a wildcard into the US Open mixed doubles draw, ending months of speculation about a partnership between two of tennis’ most recognizable names.

The announcement comes after Alcaraz confirmed on Thursday that he will return to competitive action at the New York Grand Slam. The Spaniard has missed four months of the season because of an ongoing wrist injury, but he is now set to defend his singles title at the event as well as feature in the mixed doubles field.

For Williams, the appearance offers another step in her return to the sport after a nearly four-year ‘evolution’ away from tennis during the grass-court season. Her comeback has already included a singles return at Wimbledon, where she picked up a knee injury, and later a doubles outing with her sister Venus at the Cincinnati Open. That match ended in a 6-2 1-6 10-8 loss to Marta Kostyuk and Peyton Stearns.

The six-time US Open champion also has a personal connection to the tournament, having first indicated at the 2022 edition that she would retire from the game she once dominated. This mixed doubles run now gives her another competitive outing before the singles draw begins, although the format features shorter matches than traditional Grand Slam contests.

The event will be staged from August 24-26 and will be the second edition of the redesigned mixed doubles competition. The USTA cut the field from 32 teams to 16, moved it into Fan Week before the singles main draw, and added $1 million for the winners. The format uses short sets to four games, no-ad scoring and a 10-point match tiebreak instead of a third set.

Six pairs qualified directly through combined singles rankings, eight teams received wildcards, and the final two places will be decided by a new eight-team qualifying event on August 24. The confirmed field also includes Aryna Sabalenka and Novak Djokovic, Jessica Pegula and Taylor Fritz, Iga Swiatek and Casper Ruud, and defending champions Andrea Vavassori and Sara Errani.

Last year, Vavassori and Errani retained their title by beating Ruud and Swiatek 6-3 5-7 10-6 in the final.

Jannik Sinner’s time away from the ATP Tour has now been pushed out by at least another month after injury forced him to withdraw from the US Open. The world No 1 has not played competitively since Wimbledon, with his most recent match coming on 12 July, when he beat Alexander Zverev in the final at the All England Club to successfully defend his grass-court Grand Slam title.

Sinner had originally been pencilled in for a comeback at the Canadian Open, but he stepped away from the ATP Masters 1000 event and said he needed to “prioritise his health”. In his statement, he explained: “After carefully considering all the factors together with my team, we have made the difficult decision to withdraw from Montreal. It is never easy to miss such an important event, but we believe this is the right decision to prioritise my health.”

No injury was mentioned at that stage, though he was later seen wearing a knee brace in practice, which only heightened concern over his availability for the North American hard-court swing. Soon after, he also confirmed he would miss the Cincinnati Open. “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 US Open.”

That was followed by the latest setback, with Sinner pulling out of Flushing Meadows because of the same knee issue. “We have been back on court in Monte Carlo over the last couple of days and have realised that I still need more time to recover from my right knee issue,” he said. “I’m obviously very sad and disappointed, as New York has a special place in my heart.”

Sinner has played only nine tournaments in 2026 so far. His remaining schedule currently points to Beijing in September, where he is set to defend his China Open title at the ATP 500 event starting on 28 September. If he delays his return further, Shanghai could be next on 5 October, followed by possible appearances in Vienna or Basel, both of which begin on 26 October. The season ends with the ATP Finals in Turin on 16 November, where he defended his title last year by beating Carlos Alcaraz in the final.