The tennis world was left raging on Tuesday when Adrian Mannarino and Serena Williams were both forced to retire hurt at Wimbledon in back-to-back matches on Centre Court.
Roger Federer admitted he "got lucky" after surviving a huge scare when French opponent Mannarino was forced to quit at the start of the fifth set of their first round match.
'F***ING PRESSURE': Tennis legend's brutal swipe at Naomi Osaka
Eight-time champion Federer was level at 6-4, 6-7 (3/7), 3-6, 6-2 when Mannarino called it quits after just one point in the decider.
The Frenchman, celebrating his 33rd birthday, suffered a bad fall on the Centre Court grass in the seventh game of the fourth set.
Despite taking treatment from the trainer, he was hardly able to move and had to retire in immense pain.
"It's 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," said Federer.
"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's 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."
But in a devastating twist just minutes later, Williams was also forced to retire hurt after a similar fall.
Federer was left horrified after being told about Williams' accident during his post-match press conference.
"You do have to move very, very carefully out there. If you push too hard in the wrong moments, you do go down," said Federer.
"This is obviously terrible that it's back-to-back matches and it hits Serena as well. Oh, my God, I can't believe it."
Federer felt the surface was more slippery when the roof is in use, which it had been due to rain earlier on Tuesday.
Serena Williams in tears after devastating accident
Williams' dreams of winning an eighth Wimbledon singles title and equalling Margaret Court's grand slam record were ended in the cruellest of fashion.
The 39-year-old was leading 3-1 in the first set of her first round match against Aliaksandra Sasnovich of Belarus when she slipped and had to have her left ankle examined.
Williams returned from receiving medical attention but called it a day at 3-3 and walked off Centre Court in tears.
"Brutal for @serenawilliams but centre court is extremely slippy out there. Not easy to move out there," tweeted British star Andy Murray.
American teen star Coco Gauff said she could not look as the player who inspired her to take up tennis wept as she left the stage.
"I turned away," said 17-year-old Gauff after beating British wildcard Francesca Jones in her first round match.
"I was in the gym actually stretching. I turned away because stuff like that makes me, like, really emotional."
Fans were left fuming that two matches were ruined because of problems with the Centre Court surface, taking aim at Wimbledon officials.
— Chidike Okeem (@VOICEOFCHID) June 29, 2021
How can anyone play their best tennis when you have to watch every move on slippery surface, disgrace
— Patty (@patriciantaurus) June 29, 2021
Back to back retirements on Centre Court due to wet grass. Unsafe conditions, @Wimbledon. What a disgrace!
— Beth Bois de L'Est 😺🏳️🌈🇬🇧🇺🇸🇫🇷🇪🇺🕷️😷 (@BethEastwood) June 29, 2021
Both Serena and Mannarino slipped on the same court, around the same spot. That grass surface is no joke, taking out two great players. #Wimbledon
— Iman (@iWoodyard) June 29, 2021
2 matches in a row where someone retired due to injury from conditions on Centre Court. What a joke @Wimbledon
— Joseph Clayton (@joseph_clayton8) June 29, 2021
How can Wimbledon continue allowing players to go onto Centre Court and injure themselves because of court conditions? What a joke.
— Megan Bastedo (@MeganBastedo) June 29, 2021
Click here to sign up to our newsletter for all the latest and breaking stories from Australia and around the world.