Roger Federer admits he felt "very bad" after Mannarino hurt his knee in 1R clash, says he "can't believe" Serena Williams also got injured

Roger Federer narrowly avoided an opening-round defeat to Adrian Mannarino at Wimbledon on Tuesday. Federer found himself trailing by two sets to one, but an unfortunate injury to the Frenchman saw the Swiss draw level before Mannarino ultimately retired early in the fifth set.

Mannarino, playing on his 33rd birthday, sustained a nasty fall when trailing 2-4 in the fourth set. The Frenchman grimaced in pain and struggled to walk. Although he managed to complete the set, the pain was too much for him to bear in the end.

Speaking to the media after the result, Federer, who will next face Richard Gasquet, said he felt "very bad" seeing Mannarino suffer a knee problem, considering his own struggles with similar injuries.

"The ending is terrible, something that nobody likes to see," Federer said. "I felt very bad seeing him, especially because of what I went through with my knee."

Roger Federer advances to the second round of #Wimbledon after Adrian Mannarino went down with an apparent knee injury.Mannarino tried to continue, but ultimately had to retire. pic.twitter.com/AlAZqK4Xb6

— ESPN (@espn) June 29, 2021

Minutes after Federer's win, Serena Williams took the court against Aliaksandra Sasnovich in her first-round match. Early in the first set, the seven-time champion took a tumble, one that she could not recover from.

Like Mannarino, Williams was forced to retire under unfortunate circumstances and the American great struggled to hold back her tears.

Federer, when informed about Williams' fate during his press conference, could not contain his shock.

"Come on....This is obviously terrible that it’s back-to-back matches and it hits Serena as well," he added. "Oh, my God, I can’t believe it."

Serena Williams receives a standing ovation from the crowd at #Wimbledon Williams was forced to retire in the first round of after sustaining an apparent injury. pic.twitter.com/exFZxJJZGh

— ESPN (@espn) June 29, 2021

When asked for his thoughts on the surface on Center Court, Federer pointed out that Wimbledon's grass has always been slippery in the initial rounds.

"Under the circumstances, those first two matches are always extremely difficult," Federer said. "But it’s always been like this. I feel for a lot of players it’s super key to get through those first two rounds because the grass is more slippery, it is more soft. As the tournament progresses, usually it gets harder and easier to move on."

Federer revealed he was asked how the grasscourt behaved by the referee after his match. The Swiss said he informed the referee that the court was behaving as it normally does.

However, the 20-time Major winner admitted the grass was more slippery than usual because the roof was closed. As such, he stressed the importance of moving very cautiously while playing.

"Well, as I was walking out, the referee asked me how I was feeling about the court. I said, I think the court plays normally as we know it,’ said Federer. "I do feel it feels a tad more slippery maybe under the roof. I don’t know if it’s just a gut feeling. You do have to move very, very carefully out there. If you push too hard in the wrong moments, you do go down."

I don't know if this is my last Slam: Roger Federer

Roger Federer waits at the net as Adrian Mannarino takes a tumble

Federer was also asked if he feels any pressure at Slams, given he is in the twilight of his career. The Swiss declared it was difficult to predict if Wimbledon could be one of his last Slams.

As such, the 39-year-old said he treated his match against Adrian Mannarino as a "regular" first-round encounter.

"I don't feel a particular way of pressure," Federer said. "You might think it's one of the last slams for me, nobody knows, I don't know. From that standpoint, I take it as a regular first round, which there's always pressure there, in my opinion."