Matteo Berrettini's French Open hopes were cruelly ended by injury as Matteo Arnaldi set up an all-Italian semi-final against Flavio Cobolli.
Berrettini was the only player left in the top half to have previously reached a grand-slam final having lost to Novak Djokovic in the Wimbledon showpiece in 2021.
He had rolled back the years in Paris on an emotional run after years of physical troubles but there was to be no fairytale ending as a left leg issue prompted him to pull the plug down 7-5, 5-2 to his compatriot.
The result is one of the most unexpected slam semi-finals of recent times, with world number 104 Arnaldi, who had been all but out of the tournament against Frances Tiafoe two nights ago, taking on compatriot Cobolli.
An Italian finalist looked odds on at the start of the tournament with world number one Jannik Sinner appearing unbeatable, only for the 24-year-old to fall in the second round.
But Cobolli's 4-6, 6-4, 6-4, 6-4 victory over fourth seed Felix Auger-Aliassime guaranteed an Italian finalist on Sunday and a first all-Italian men's semi-final in grand slam history.
Tenth seed Cobolli could take confidence from having beaten Canadian Auger-Aliassime in both their previous matches, but he had never defeated a top-10 player in a best-of-five-sets match.
That did not look like changing when Auger-Aliassime led by a set and a break but Cobolli responded with a run of four games in a row and did not look back.
The 24-year-old, who reached his first grand slam quarter-final at Wimbledon last year, was particularly good under pressure, saving eight of the 11 break points he faced.
Cobolli found his game once the roof was shut following the first set – a provision not afforded to world number one Aryna Sabalenka, who struggled with the wind in her shock loss to Diana Shnaider earlier.
"I think we played two different matches today," said Cobolli. "The first set was incredibly windy, it was incredibly tough to play."
"I went to the toilet to think a bit, to change something. I just say to myself to fight. I felt like this is the chance of my life and I have to give everything. Today I did it so I'm really happy."
Arnaldi went into his match against Berrettini having spent 17 hours and 42 minutes on court – nearly two hours longer than the previous record for time taken to reach the last eight at a slam.
He lost the opening three games but hit back strongly, and the first sign of real trouble came when Berrettini took an injury timeout at 1-2 in the second set.
It became increasingly clear that he was compromised and, with tears in his eyes, he shook hands before the end of the second set.
Arnaldi said: "It is a tough one. We both played a lot, so it is normal to be not at our best, but you never wish for someone to end the tournament like this."
"He did an amazing tournament. We are doing such a good job in Italy. I am sorry for him and I hope he recovers because soon it is the grass, and he is going to be very tough to play."
