They had played on and on, through 6 1/2 hours of ho-hum hold after ho-hum hold, during the second-longest match in the history of a tournament that began in 1877, all the way until the never-ending serving marathon did, finally, end at 26-24 in the fifth set Friday, with Anderson claiming the most important of the 569 points - the last.
The result came two days after Anderson stunned eight-time champion Roger Federer in four hours and five more sets, saving a match point in the process.
The 32-year-old Anderson is the first South African man since Brian Norton 97 years ago to reach the Wimbledon final.
The Djokovic-Nadal semi-final was massively delayed while Isner and Anderson monopolised Centre Court, and the South African now has to wait until Saturday afternoon to see who will face him in the final. Nadal then saved a single match point with a handsome drop shot in the following game.
"I don't really know what to say right now", a clearly drained Anderson said immediately after the match.
Then Anderson served out the victory, with Isner sailing a forehand wide on match point.
They walked out under a closed Centre Court roof at around 8pm, with officials anticipating darkness will fall before their semi-final match is resolved.
"At the same time, I'm through to the final. Wow".
"It's up to me to not let this match linger, going forward, when I get back in America playing on the hard courts, which is my favorite surface", Isner said as he shifts focus to the U.S. Open starting in late August.
Serbia's Djokovic had beaten the current world No. 1 in the 2011 final, the last time Nadal advanced beyond the fourth round until this year. He'll resume his duel against the Spanish World No.1 at 2pm SA time on Saturday.
The Serb took the first set 6-4 before the Spaniard hit back in the second, winning 6-3. It was clear very few things separated the two players. He criticized the lack of a deciding-set tiebreaker at Wimbledon, the Australian Open and the French Open.
The first teaser that this game was not going to be short or straightforward came in just the third game when Isner put pressure on Anderson's serve by taking the ball early. It was the longest semifinal in Wimbledon history and set off a new round of debates regarding rule changes.
He broke Isner with the match tied 24-24 in the fifth set, and then held Isner off in the 50th game.
In nine years since Roddick's last Grand Slam final, USA women have reached a combined 21 Grand Slam finals (16 via Serena Williams).