Swiss Stan Wawrinka at 32 years and 75 days, is the oldest finalist at Roland Garros since Nikola Pilic in 1973 following his dramatic victory over Andy Murray.
The world number one was beaten 6-7 (6-8) 6-3 5-7 7-6 (7-3) 6-1 in four hours and 34 minutes.
It was a repeat of last year’s semi-final, which the Briton won before going on to lose the final to Novak Djokovic.
Former champion Wawrinka faces Rafael Nadal or Dominic Thiem in Sunday’s final.
The two served up an epic encounter that had fans on the edge of their seats, and Wawrinka’s superior fitness proved the difference as he dominated a fatigued Murray in the final set.
The first set was a back-and-forth affair that lasted 68 minutes as both players flashed their immense talent. While Wawrinka appeared to have the upper hand in the rallies, his opponent played cleaner tennis, not making many mistakes.
That proved crucial in the tiebreak, which was very close but eventually went Murray’s way following a poor return from the Swiss star.