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.

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.

Brandon Nakashima has ensured the Cincinnati Open will produce a first-time ATP Masters 1000 champion after ending Taylor Fritz’s run in the quarter-finals.

With world No 1 Jannik Sinner and defending champion Carlos Alcaraz missing because of injury, the draw had already been weakened further by early exits for Alexander Zverev, Novak Djokovic and Daniil Medvedev. Fritz, the 2022 Indian Wells Open winner, had stood as the last former Masters champion left in the field before Nakashima removed him.

The 25-year-old is now within reach of a second straight ATP 1000 final after finishing runner-up at the Canadian Open. He beat Fritz 7-6 (11-9), 4-6, 6-3 in two hours and 13 minutes, and afterwards explained the confidence he has taken from recent matches.

“Just getting a lot of confidence from all the matches I have been playing,” Nakashima said after his 7-6 (11-9), 4-6, 6-3 win in two hours and 13 minutes. “When it came down to the wire in the third set, just tried to trust my game fully and just really proud of how I ended the match.”

That result has lifted Nakashima to a new career high of No 22 in the official ATP Rankings, and his Cincinnati run means he is now set to move into the top 20. He has already climbed six places to No 16 in the Live Rankings, and a place in the final would take him as high as No 11.

Nakashima must first get past another American, Frances Tiafoe, in the semi-finals. Tiafoe beat 10th seed Lorenzo Musetti 7-6 (7-2), 7-5 and will also move back inside the top 20 next week after rising five places. He started the event at No 23 and can climb to No 11 if he wins the title.

The other semi-final will be between Cobolli and Fils. Cobolli moved to a career-best No 6 in the Live Rankings after beating Tommy Paul in three sets, while Fils rose seven places to No 14, matching his career high, after a straight-sets win over Thiago Agustín Tirante.