Having made a slow start, Hurkacz was on course to level the match at two sets apiece when he dived for a volley at the net in the fourth set tiebreak to go 8-7 up, but landed badly and immediately clutched his right knee.

He limped on after a lengthy medical timeout, but was forced to throw in the towel at 7-6(2) 6-4 2-6 6-6 having gone down 9-8 in the tiebreak.

"It's tough to win a match like this against a friend. We were playing super good in the fourth set. We had some great points. He was jumping everywhere," said Fils.

"I'm really sorry for him. I hope he will recover quickly."

The big-serving Pole, who beat Roger Federer to reach the 2021 semi-finals and took a set off seven-times champion Novak Djokovic in the last 16 last year, had primed himself for more major damage this year after a run to the Halle final last month.

Hurkacz showed flashes of his best form after a lacklustre effort in the first two sets but could not see off the 20-year-old Fils on a sunny afternoon, joining sixth seed Andrey Rublev and eighth seed Casper Ruud in making a premature exit.

Fils became the youngest Frenchman to reach the Wimbledon third round since 2005, when both Richard Gasquet and Gael Monfils did so as teenagers but his celebration was understandably muted.