By the time the fourth set had begun, it was clear that this match, as some regarded it, was no warm-up act for the Nadal-Djokovic semifinal to be played later on the same court - not a starter for the main course.
In contrast, Anderson didn't concede a break-point in this set, taking one of the six offered by Isner under fading light.
When Isner finally slapped a tired forehand wide at 7.46pm local time, there were no wild roars, no fist pumping and no raised arms in celebration from Anderson. "I mean, it's just who's going to outlast each other", said Anderson, a 32-year-old from South Africa who is seeking his first major trophy. John is such a great guy and I really feel for him because, if I'd been on the opposite side, I don't know how you can take that, playing for so long and coming up short.
South African eighth seed Kevin Anderson has reached his first Wimbledon final, beating American ninth seed John Isner 7-6 (8/6) 6-7 (5/7) 6-7 (9/11) 6-4 26-24 in the longest semi-final in the tournament's history.
When their semi-final ticked past the 5-hour 31-minute mark, it beat the previous mark set by Marin Cilic and Sam Querrey in the third round in 2012.
Djokovic missed a return as the clock ticked to 11pm but on the final lung-busting rally it was Nadal who faltered.
There, they face the victor of the match between Alicja Rosolska and Abigail Spears and the third-seeded Czech pair of Barbora Krejcikova and Katerina Siniakova.
The last set alone lasted five minutes shy of three hours and Anderson said it was unfair on both players.
John Isner had his streak of consecutive service game wins ended at 110 by Kevin Anderson, who took a 5-3 lead. The former Bulldog broke right back to even the set once again.
This one seems rather tidy by comparison: Anderson won 7-6 (6), 6-7 (5), 6-7 (9), 6-4, 26-24.
Isner would like the US President, a serious tennis fan, to be in the Centre Court crowd as his guest for what promises to be another battle of big serves against Kevin Anderson.
Isner was the last remaining American in the men's bracket.
That didn't happen through the first 12 games of the last set, with each player holding serve to reach 6-all.