Eight-time champion Roger Federer avoided a huge Wimbledon upset as injury robbed France's Adrian Mannarino of the chance to earn a memorable win.

Sixth seed Federer, 39, trailed 6-4 6-7 (3-7) 3-6 4-2 when Mannarino slipped and injured his knee.

It was a cruel blow for Mannarino, who had played brilliantly in the second and third sets to put him within touching distance of a first victory over Federer in seven attempts.

Although the fourth set already looked beyond the Frenchman, there was no certainty that Federer - who has suffered his own knee issues over the past 16 months - would have maintained the momentum.

"It is awful, it shows that one shot can change the outcome of a match, a season, a career. I wish him all the best," said Federer.

"I hope he recovers quickly and we see him back on the courts. He could have won the match, he was the better player, I got lucky."

A sympathetic Centre Court crowd gave a heartfelt ovation as Mannarino, on his 33rd birthday, limped off court.

The Swiss 20-time Grand Slam champion will play 35-year-old Frenchman Richard Gasquet, who beat Japan's Yuichi Sugita, in the second round.