Novak Djokovic won a gruelling five-set battle with Felix Auger-Aliassime to set up a semi-final with reigning Wimbledon champion Jannik Sinner.
It went down to the wire, all the way to a fifth set tiebreak in the longest quarter-final in Wimbledon history.
Djokovic, who grew appeared agitated at points during the contest, needed a medical time out early on but eked out a victory to beat the Canadian 7-6 (12-10) 3-6 6-3 6-7 (5-7) 7-6 (10-4).
In the first set he clutched his calf and called for the trainer to tend to it. He couldn't find a break of serve but eventually won an extended tiebreake.
The Serbian then coughed up a break and Auger-Aliassime snatched the second set away from him. Djokovic vented his frustration when he objected to officials closing the roof at the end of that second set, arguing there was still enough light for Centre Court to remain open.
He put that behind him to take a two sets to one lead and was then a break up in the fourth set, on the brink of victory. But Auger-Aliassime shrugged off mistakes to fight back and pocket the fourth set, winning the second of three tiebreaks.
They remained in lockstep in the decider as the tension ratcheted up to new extremes. A breath-taking final tiebreak unfolded, as the tournament curfew loomed, with Djokovic and Auger-Aliassime meeting each other in tremendous rallies.
It was the Canadian who finally faltered as an almost-spent Djokovic sealed victory, an extraordinary performance at the age of 39.
His dream of a record-breaking 25th career Grand Slam title, by the most slender of margins, lives on.
Afterward Djokovic said he won "with racket and a lot of heart. A lot of management of the nerves and extreme tension you feel in these kind of matches".
"Towards the end it was really anybody's game," he said. "These are the kind of moments that I still play tennis for. For sure.
"I wish it was finals so I don't have to worry about how the body will feel tomorrow. I'm happy, happy that I won.
"It was honestly one of the best matches I was part of on this court in my career.
"I have no energy left... right now it's all business I still have to recover, I'm still in the tournament and I have the best player in the world in a few days time."
Defending champion Sinner fought off the challenge of veteran German Jan-Lennard Struff to win 7-5 7-6 (4) 6-3.
Sinner made 26 unforced errors and had to save a set point in the second set against a player ranked 74 and making his Grand Slam quarter-final debut.
At 36, Struff was the oldest man to reach this stage at a major for the first time in the open era having defeated eighth seed Daniil Medvedev and claimed three five-set victories.
His power and ability at the net caused problems for Sinner, who could not find a rhythm. The Italian broke through to lead 2-1 in the second set, only for some big hitting from Struff to help him hit straight back.
Only a very fortunate mis-hit forehand that dropped inside the baseline prevented Sinner from being in real trouble in his next service game, while his own serving helped him save a set point at 5-4.
Sinner finally began to look more comfortable in the third set.
"First of all a very, very tough player to play against," said Sinner. "In the beginning I felt like he started better than me, I was struggling a bit. I tried to get into the match, I was serving a bit better, tried to stay there mentally, and of course very happy to be back in the semi-finals here."
Naomi Osaka's hopes of a Wimbledon title this year ended in the quarter-finals as she lost to Karolina Muchova.
Former world No 1 Osaka put her name in the mix for All England Club success after she knocked out Aryna Sabalenka in the fourth round to progress into the last eight in SW19 for the first time.
However Muchova stood in the way of Osaka and, having made the quarter-finals in London twice before, it was a case of third time lucky for the 29-year-old who took a 7-6 (4) 6-4 win.
It represented a missed opportunity for Osaka, who won twice at the Australian Open and US Open during the first half of her distinguished career before a lengthy career break.
This defeat means she remains without a slam title since 2021.
Coco Gauff recovered from a serving crisis to blast her way into her first Wimbledon semi-final with a 4-6 6-3 6-3 victory over American compatriot Jessica Pegula.
Gauff served up six double faults during her first seven service games, but the two-time Grand Slam champion wrestled back control and seven aces helped book her place in the last four.
World No 7 Gauff hadn't managed to reproduce her best form on grass since bursting onto the scene at Wimbledon as a 15-year-old in 2019. She'd never gone beyond the last 16 at SW19 until this year, but roared in delight after this latest three-set success.
"Honestly, it's pretty insane, considering I hadn't won a match on grass in two years before this tournament," Gauff said.
"After seven years playing this tournament, it is finally the first time I can walk on Centre Court and not feel nervous. I don't know if I'm becoming a vet!"
