Roger Federer has conceded that he was lucky to progress against his unfortunate Wimbledon first round opponent Adrian Mannarino.
The eight-time former champion toiled against the energetic Frenchman, who at one stage led two sets to one against the Swiss legend.
However, with Federer leading in the fourth, Mannarino fell awkwardly, causing some damage to his knee which required treatment.
Federer's Olympics withdrawal raises more doubts about what lies ahead
- Federer survives major scare to progress after Mannarino injury
- 'An honour and a privilage' - Barty on opening Centre Court
- Brit round-up: Evans into second round with straight sets win
After attempting to power on, the 33-year-old was eventually forced to retire at the start of the fifth, handing Federer a walkover.
Speaking to the BBC after the match, Federer offered his condolences to his opponent, who he admitted was the “better player” on the day.
"It is awful and shows one shot can change the outcome of a match, season, career and I wish him all the best and hope we see him back quickly - he was the better player, he could have won, I got a bit lucky.
"That's how it goes sometimes, you don't get many walkovers and try not to have it happen to yourself, it is a reminder how quickly it goes but I am obviously happy I can get another match here - I enjoyed myself today and it was great fun until the end."
Mannarino suffered a knee injury against Federer
Image credit: Getty Images
"I tried to cut down the length of points, he found a nice groove from the baseline with that shovel backhand and did the same to me, once I got the break I was able to loosen up a little bit.
"It was a very up and down match and overall we were both wrestling to see who could enjoy the baseline, I felt I had to adjust my game more than he did his and that's credit to him.
Federer now faces Richard Gasquet who beat Yuichi Sugita in four sets.
Watch daily evening highlights on Eurosport 1, plus the men's and women's finals live on Eurosport 2. All coverage is also available to stream via eurosport.co.uk and the Eurosport app
Murray, Djokovic in, Williams, Federer out - who's playing tennis in Tokyo?
'Grand Slams are everything' - Djokovic ready to join Federer, Nadal on 20 majors