Jannik Sinner dug himself out of a hole to defeat Denis Shapovalov and reach the fourth round of the US Open.

The defending champion has not lost a Grand Slam match on hard courts for two years, but he looked in real trouble at 3-0 down in the third set with the pair locked at one-set all.

Canadian Shapovalov, who had won their only previous meeting at the Australian Open four years ago, had a chance to make it 4-0, but Sinner saved the break point and won nine games in a row on the way to a 5-7 6-4 6-3 6-3 victory.

“It was a very, very tough match today,” said the world No 1 . “I know Denis since quite a long time. I knew I had to play at a very, very high level. I’m very happy that I managed to win. He started off very well. I just tried to stay there mentally.”

Sinner again did not have his best serving day and, after clawing his way back from 2-5 in the opening set to 5-5, with Shapovalov unhappy about a foot fault call on a crucial point, the Italian double-faulted to lose the opening set.

Sinner has only lost one match to a player other than Carlos Alcaraz this season – to Alexander Bublik on grass in Halle – but he trailed Grigor Dimitrov by two sets to love at Wimbledon before the Bulgarian suffered a heart-breaking injury.

“I’m not a machine,” said Sinner with a smile. “I also struggle sometimes. Today I felt like from my side I didn’t struggle. I was playing great tennis, and he also.”

Shapovalov was left with mixed feelings, saying: “It’s obviously a tough loss. He’s number one for a reason, first of all. I had my chance. Was up in the third set. Obviously he played great to come back.

“This is the goal, just to have this level more consistently. I know I’m able to play this brand of tennis, this level of tennis. In a way, I’m happy. Obviously sad, as well, that I lost. But it’s definitely a good step forward for me.”

Sinner will next play either Kazakhstan’s 23rd seed Alexander Bublik or American 14th seed Tommy Paul in the next round.

Tenth seed Lorenzo Musetti has had a strong first week and he benefited from the retirement of fellow Italian Flavio Cobollo from injury in the third set of their contest.

Andrey Rublev is showing improved form again after a difficult period, but the 15th seed needed five sets to overcome Hong Kong’s Coleman Wong and reach the fourth round for a fourth straight year.

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