Sinner, who noticed his opponent was struggling, immediately came over to the other side of the court to check on Zverev. He was holding his knee as he lay on the grass, with Andre Agassi on BBC commentary explaining: “That’s a hyperextension, when that happens you’re laying on the ground hoping the pain doesn’t indicate it’s something you’re not going to recover from.”
Zverev got back to his feet, however, and didn’t he require any medical treatment in a third set of a match he was feeling comfortable in.
But the 29-year-old could not get back to grips with the contest and gave up the very first break of the final, before eventually losing the third set 6-3.
Up until that point, the top two seeds had played out a throwback serve-fest.
There was only one break point in the first two hours of the contest, which was saved, and the opening two sets required two tiebreaks.
That tide changed once Zverev was struck down, but he opted against treatment from a physio and instead tried to play through any pain.
Shortly after, Zverev threw his racket in anger, having gone from competing in a 50-50 clash to fearing the worst with Sinner then one set away from retaining his title.
Zverev had never gone past the fourth round at the British Slam before arriving in SW19 two weeks ago.
But a regained confidence from victory in Roland Garros has provided him with the platform to challenge for Majors.
Zverev dropped just one set after the first round before walking onto Centre Court, taking out his bogey player Taylor Fritz and British sensation Arthur Fery in the process.
He began the final by taking a set off Sinner, the first time he has managed to do so since last October in Vienna. Six matches had taken place since. But the worrying fall caused Zverev to decline dramatically for the rest of the set.