Pegula has an image for the way Sinner moves, and it has nothing to do with tennis. On The Player’s Box podcast, the American compared the Italian’s footwork to a sport played on snow.

“He literally looks like he is skiing. I don’t think anybody has moved [like that]. I guess Novak [Djokovic] is probably the closest, but Jannik looks like he is skiing on a tennis court,” Pegula said, speaking on the show alongside Madison Keys.

For the two Americans, that is also why Sinner’s knee has given in. Pegula pulled no punches on the biomechanics.

“I feel like the way that he moves is not normal, so I don’t really think it’s that shocking that he possibly has a little something going on,” she said.

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Keys would break trying

Keys, who won the Australian Open in 2025, said she could not even imagine attempting what Sinner does on hard courts without something snapping.

“He moves in a way that I feel is not possible; my body would never do it because I would break.”

She then described the specific sequence that leaves her shaking her head.

“The way that he can run into corners or slide into corners and stop and then cut, I would still be running into the stands,” Keys told the podcast.

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A season cut short in October

The context for the biomechanics talk is that Sinner is done for the year. The world No. 1 announced on 6 October that he was shutting down his 2026 campaign to treat the knee.

“Me, together with the doctors, have decided that I need a course of treatment for my knee, which means that the 2026 season is officially over,” Sinner wrote in the statement on his official channels.

He had not played a match since beating Alexander Zverev in the Wimbledon final in July, missing the US Open and the entire North American swing. The withdrawal from the China Open on 25 September was followed by pull-outs from Shanghai, the Paris Masters, the ATP Finals in November and the Davis Cup Final 8.

Pegula framed the situation as a reality check for everyone who had come to see the Italian as untouchable.

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“I feel sometimes we think that nobody is ever going to beat him, and then something like this happens, and you come back to the reality that it’s really hard to stay healthy, especially at their level.”

Sinner’s statement said he would do everything possible to get back to 100 per cent, with no return date attached.

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