South African Kevin Anderson won the second-longest match in Wimbledon history by outlasting American John Isner to reach the men's final.
They slugged it out on Centre Court for six hours and 35 minutes before the eighth seed came through 7-6 (8-6) 6-7 (5-7) 6-7 (9-11) 6-4 26-24.
The final set alone lasted for two hours and 50 minutes.
Anderson, 32, will face either Rafael Nadal or Novak Djokovic in the final on Sunday, July 15.
The match duration beats the 2012 third-round epic at Wimbledon between Marin Cilic and Sam Querrey - which lasted five hours and 31 minutes - and also smashed the previous record for the longest semi-final at SW19, when Djokovic needed four hours and 44 minutes to beat Juan Martin del Potro in 2013.
It is the third-longest match in tennis history, falling short of the 11 hours and five minutes that it took for Isner to beat France's Nicolas Mahut 70-68 in the fifth set in their first-round match at Wimbledon in 2010.
The match was also just shorter than a Davis Cup first-round match between Argentina's Leonardo Mayer and Brazil's Joao Souza, which went on for six hours and 43 minutes in 2015.
Anderson, who was runner-up to Nadal in last year's US Open final, becomes the first South African man to reach the Wimbledon decider since Brian Norton in 1921.
He finally broke the 33-year-old American in the 49th game of the decider after coming close in a couple of earlier games and looked impassive as he held his nerve to secure victory.
Anderson and Isner are old friends and there was little celebration from the South African as he went over to the other side of the net to embrace his beaten rival.
He came into the match having beaten Roger Federer in four hours and 14 minutes on Wednesday - and had been on court for three hours and 29 minutes in his fourth-round win over France's Gael Monfils.
In contrast, Isner's longest match was three hours and 46 minutes against Belgium's Ruben Bemelmans in round two, where he had to save two match points.
"I don't know what to say right now. just playing like that in those conditions was tough on both of us," he told BBC Sport.
"You feel like it is a draw, but someone has to win. John is a great guy and I feel for him. If I was on the opposite side, I don't know how you take it - getting through something like that is quite different.
"I have known John for such a long time, he is a great guy. To be honest he has pushed me through my career and had a great one himself.
"I have pushed myself harder because of the success he has had. I have to say congratulations to John on a great tournament and hopefully he can come back stronger."
Is it fair on the players not to have a final set tie-break?
Three-time Wimbledon champion John McEnroe: "I hope this magnificent effort by these two experienced and very fit professionals allows the powers-that-be to make a change. For them and for those players coming up.
"I believe that strongly, for our sport to continue to have as many people as possible watching. You can't say playing a tie-break would not have been a magnificent end to this game. The fifth set doesn't have to end six-all, it could be 10-all.
"This will have an effect on Anderson's performance on Sunday. Rules should be made to benefit the players."
Former Wimbledon semi-finalist Tim Henman: "When we had the first Isner match, we didn't think we would see that again. But in the context of this game, it's going to be incredibly challenging for Kevin Anderson in the final and I think it will be on the agenda for Wimbledon to discuss after the Championships."
The pair came into the match with a total of 248 aces between them and it was no surprise that serving was to the fore once again.
With break-point chances few and far between, the opening two sets went to tie-breaks. Leading 4-3 in the third set, Anderson eventually broke to end Isner's run of 110 consecutive service holds.
It left him serving for the set - but he missed his chance and it went to another tie-break, which Isner won.
Anderson broke early in the fourth set for a 3-2 lead, only for Isner to break straight back.
The South African broke again to make it 5-4 - and this time he held serve to send the match to a decider.
As fatigue started to creep into both players' games, it took until the 15th game before Anderson earned the first break-point chance, which Isner saved with ace number 42.
Anderson had another chance in the 21st game - and again in game 34 - but the American held firm.
However, he started to look wearier on his serve and - eventually - Anderson seized his opportunity.
Anderson (left), and Isner, in a show of sportsmanship after the epic semi-final clash at the Centre Court.