Rafael Nadal defied his family's wishes by battling through injury to record a remarkable five-set victory over Taylor Fritz - but gave no guarantees he will take to Centre Court for his semi-final against Nick Kyrgios.
Nadal came into the match with an abdominal problem and looked set to retire at a couple of moments but somehow recovered to claim a 3-6 7-5 3-6 7-5 7-6 (4) victory after four hours and 20 minutes.
The Spaniard's father Sebastian gestured to his son to call it a day when he went off for treatment midway through the second set, and Nadal shook his head towards his box after losing the third, with Fritz seemingly waiting for a handshake.
"They told me I need to retire the match, yes," said Nadal. "For me it was tough to retire in the middle of the match. Not easy even if I had that idea for such a long time. It's something that I hate to do. So I just kept trying, and that's it."
The result kept alive Nadal's hopes of becoming the first man since Rod Laver in 1969 to win all four grand slam titles in the same year, but much will depend on how he recovers over the next couple of days.
"Tomorrow I'm going to have some more tests," he said. "But it's difficult to know. I am used to having things and I am used to holding pain and to play with problems. Knowing that, when I feel something like I felt, that is because something is not going the proper way in the abdominal.
"I had these feelings for a couple of days. Without a doubt, today was the worst day. It has been an important increase of pain and limitation.
"Nothing can be fixed when you have a thing like this. I'm proud about the fighting spirit and the way that I managed to be competitive under those conditions."
Asked if he thought he would be able to take on Kyrgios, Nadal said: "I need to know different opinions and I need to check everything the proper way. That is even something more important than winning Wimbledon, that is the health."
Tape had been evident on Nadal's stomach during his fourth-round victory over Botic van de Zandschulp but there were no early signs of discomfort as he eased into a 3-1 lead over 24-year-old Fritz, who was playing in his first grand slam quarter-final.
The American began to put real pressure on Nadal's serve, though, and turned things around to win the first set with a run of five games in a row.
He then retrieved another early break at the start of the second but Nadal somehow managed to take that set before hopes of a miraculous recovery faded again in the third.
Fritz, who was unable to beat Novak Djokovic in a similar scenario at the Australian Open last year, knew the match was there for the taking but he found himself playing catch-up in the fourth and Nadal, who took anti-inflammatories and pain killers, managed to lift his level in the decider.
"I'm playing great," said Nadal. "I am enjoying a lot. The level of tennis, if we put away the problems - something that's difficult - the level of tennis, the feeling that I am having with the ball on my hand is honestly great. I am feeling myself playing very well."
Fritz had ended Nadal's 20-match winning start to the season in the final of Indian Wells in March when the Spaniard struggled with a fractured rib, but the emotions were very different here.
"Certain parts of the match I felt like maybe I just needed to come up with more, do more," said Fritz. "I left a lot kind of up to him, and he delivered. It was a great match. Honestly, probably hurts more than any loss I've ever had."
Up next for Nadal is Nick Kyrgios, who is just one match away from a place in the Wimbledon final after steaming past Cristian Garin in straight sets.
The controversial Australian, whose antics this fortnight have thrilled and appalled in equal measure, reached the last four of a grand slam for the first time with a commanding 6-4 6-3 7-6 (5) victory.
Kyrgios, now 27, has long been regarded as having all the talent to win major tournaments, but almost none of the application.
But after cruising past Garin - and armed with a 2-0 winning record over most likely final opponent Novak Djokovic - the self-styled bad boy of tennis might finally be about to come good.
"I never thought I'd be in the semi-final of a grand slam," he said. "I didn't go about things great early in my career and I thought my ship had sailed. I'm really proud of how went about things out here."
His run to the semis may have been marred by run-ins with umpires, line judges, opponents, the media, the crowd and the fashion police.
But Kyrgios was on his best behaviour - relatively speaking - on Wednesday, even striding on to Court One in white trainers rather than his preferred red ones which breach the strict SW19 dress code.
Garin, the world number 43 from Chile, had never won a match at Wimbledon before but got a lucky break when his first-round opponent Matteo Berrettini, the eighth seed and among the favourites for title, withdrew due to Covid.
The draw opened up invitingly for the 26-year-old, who comes from a country which does not even have any grass courts, but his luck ran out against Kyrgios.
Yet in a bizarre start to the match Garin won the first eight points to lead 2-0.
But Kyrgios, amid the constant chuntering and gesticulating towards his box, broke back for 3-3.
Kyrgios, again taking far longer between serves than he had in his fiery third-round win over Stefanos Tsitsipas, was then gifted the opening set by four unforced errors from his increasingly nervous looking opponent.
An early break in the second, to love, courtesy of more loose shots from Garin, put Kyrgios in complete control.
Garin, to his credit, proved a tough nut to crack in the third and took it the distance, and it would not be a Kyrgios match without the inevitable disputed line call - this time on match point - before a Garin forehand floated wide to rubber-stamp his opponent as a Wimbledon semi-finalist.
