The No. 8 seed beat the No. 9 Isner 7-6, 6-7, 6-7, 6-4, 26-24.
Well, considering it went on for six hours and 35 minutes, the short answer is, you don't!
"I hope this is a sign for Grand Slams to change". "At the end you feel like this is a draw between the two of us".
The crowd grew restless as it left Centre Court ticket-holders waiting far longer than anticipated to watch icons of the sport Rafael Nadal and Novak Djokovic resume their enduring rivalry with a 52nd meeting on the ATP Tour in the other semifinal.
Isner appeared to be struggling at times from 12-all to 18-all, but he held firm on his serve as Anderson, playing his second-consecutive five-set match, found a second (or third or fourth) wind. He beat the defending champion 2-6, 6-7, 7-5, 6-4, 13-11 in a match that lasted more than four hours.
Djokovic, meanwhile, is seeking a fifth final at the All England Club and 22nd at the Slams.
The match between Isner and Anderson, who had been trying to become the first South African to reach the Wimbledon title match since Brian Norton in 1921, featured 102 aces, with only 22 rallies going to nine points or more.
Convicted son-in-law of Nawaz Sharif held in Rawalpindi
Sharif's son-in-law Capt (retd) Muhammad Safdar was jailed for one year rigorous imprisonment for not cooperating with the NAB. Sharif along with Maryam had gone to London last month to see his ailing wife Begum Kulsoom Nawaz.
The eighth seed will face either twice champion Rafael Nadal or three-times victor Novak Djokovic in Sunday's final.
Predictably, the games went with serve in the second set, with Anderson earning a break-point in the ninth, but failing to capitalise.
Anderson will play again in the final on Sunday - hopefully there, a victor will be decided in four sets or less.
Wimbledon's lack of a fifth set tiebreaker in one of the things that makes the major unique.
John Isner and Kevin Anderson simply refused to lose.
After saving two set points in the third set tiebreak, Anderson blew his first set point at 8-7 with a double fault. Finally, Isner wrapped it up 11-9 with a deep return that set up the point.
Anderson had break points in the 15th, 21st and 35th games of the decider before taking victory when a tired Isner hit long.
"Rafa and Djokovic, I don't even know, can they finish tonight?"
"I think it's long overdue", Isner said.