Although both players had shown an ability to make inroads on their opponent's serve, the fifth set turned into a marathon featuring one service hold after another. Having the roof shut meant every sound was amplified as it ricocheted off the dome - the thwack of ball off racket, the players' grunts, the spectators' applause.
He stands at 0-5 with Nadal and 1-5 against Djokovic.
That total was more than double the number he has had in any match against Nadal (11, on two occasions).
Nadal missed five break points in the decider and was eventually punished as 12-time Grand Slam champion Djokovic reached his first major final since the 2016 US Open.
Isner won that best-of-three match 7-6, 6-1.
Additionally, Anderson called for a change in the tournament format so that players won't have to go through such long matches.
Djokovic, the Wimbledon champion in 2011, 2014 and 2015, will be bidding for a 13th Grand Slam title when he faces Anderson on Sunday.
Djoker was getting fired up.
"It really could have gone either way", Djokovic said.
Nadal however was left angered by the decision to leave the roof closed, despite there being no hint of rain on the radar.
Play will begin at 5.30 pm IST, with the women's final to follow. "But as I understood, they already made a decision".
"I have to recover as much as I can for the final now". A few days' rest, maybe more than that, and I'll recoup and try to get all healed up again.
Incredible Moment Of Sportsmanship As Rafa Nadal Into Wimbledon Semi
But the same goes for the 32-year-old Anderson, who also reached his first Wimbledon quarterfinal, and now semifinal, this week. After nearly five hours, I fell down. "I don't want to stop here". "It was great to me to play Rafa in this level".
The pressure is on Nadal in the early stages of this fourth set and his down the line shots are up and running. He stayed the course incredibly well, played very well. "I'm trying to digest that first, enjoy it, and we'll think about the next one". "I wanted to play in the same conditions".
"At the same time, I'm through to the final. Wow".
"I don't know if I'll be the clear favourite in that one. That's something I have to keep reminding myself". I apologize if I'm not more excited right now.
"When you play with that intensity, with that level of risk, that level of passion, sometimes you go over, no?"
"I have nothing to complain about". What can I say about that? That's all. That's sport.
"It was really tough for both of us". That's it. Today was for him.
The previous longest semifinal match at Wimbledon was in 2013, when Djokovic beat Juan Martín del Potro in 4 hours, 44 minutes.
A significant part of the problem was a painful right elbow that forced him off the tour for the second half of 2017 after he stopped playing during his Wimbledon quarterfinal. He had surgery in February, but his results were still shaky.
Until now, that is.
"There was a dialogue, yeah", said Djokovic after his 52nd career clash against Nadal.
Arriving at the gates on Friday morning, he said: "Rafael Nadal". I deserve it, too. He converted his second set point when Nadal netted a backhand, minutes past the tournament's 11 p.m. curfew.
"It's hard to pick the words", said Djokovic, who has won his past eight five-setters at Wimbledon. I just expressed my opinion because they asked for my opinion.