Third seed Alexander Zverev reached the French Open semi-finals for the second successive year after surviving teenage sensation Carlos Alcaraz's fightback.
Continuing his quest for a maiden Grand Slam title, Zverev won 6-4 6-4 4-6 7-6 (9-7) against the sixth seed.
The German, 25, served strongly and was superb from the back of court, but 19-year-old Alcaraz made too many errors.
A semi-final against defending champion Novak Djokovic or 13-time winner Rafael Nadal, who meet next, awaits Zverev.
"I knew I had to play my absolute best tennis from the start," said Zverev.
"He is an incredible player and I told him at the net he will win this tournament many times, not just once.
"I hope I can win it once before he does - and starts beating us all."
Spain's Alcaraz improved his level to force a fourth set which hung captivatingly in the balance and created a fervent atmosphere on Court Philippe-Chatrier.
A double fault from Alcaraz on a break point at 4-4 gave Zverev an opportunity to serve out victory, but the youngster broke back and then sent the set into a tie-break.
The pair produced the highest quality of the whole contest amid the tension, with Zverev taking his second match point with a sweet backhand winner.
World number three Zverev lost to Greece's Stefanos Tsitsipas in the semi-finals at Roland Garros last year and reached the same stage by producing his best performance of this tournament.
Now, after beating Alcaraz to earn his first win over a top-10 opponent at a major, Zverev will aim to go one step further.
The Olympic champion has lost three of his four previous major semi-finals, and when he did progress, was beaten in the 2020 US Open final by Austria's Dominic Thiem.
Alcaraz has been the talk of the men's game in an impressive season which has seen him claim a tour-high four titles and win 32 of 35 matches going into the second major quarter-final of his career.
But he paid the price for being far below his best in the opening two sets against Zverev, who avenged defeat in their recent encounter at the Madrid Open final.