Stan Wawrinka produced an impressive display to beat former world number one, Daniil Medvedev, for his first top-10 win since 2020 in Metz on Thursday.
The three-time Grand Slam champion, currently ranked 284th in the world after injury problems, missed a match point in the second set before winning 6-4, 6-7 (7/9), 6-3 to reach the quarter-finals.
Wawrinka came through two rounds of qualifying to make the main draw of the ATP event and has now won four straight matches.
"I'm very happy with the level of play that I managed today," said Wawrinka, who missed 12 months from March 2021 with a tendon injury.
"It's for moments like this that I did everything to come back."
Top seed Medvedev hit back in a dramatic second-set tie-break in a topsy-turvy contest.
Wawrinka saw two break points for a 4-0 lead in the decider come and go before being pegged back to 3-3.
But the 37-year-old held his nerve and broke again, completing the victory on his third match point.
"Stan was better than me and he won," said Medvedev. "I tried to hang on. I had opportunities but it wasn't good enough.
"But respect to Stan, I didn't think he was 37."
Wawrinka will next face Sweden's Mikael Ymer in his first ATP quarter-final since January 2021.
Earlier Thursday, second seed Hubert Hurkacz ended former US Open champion Dominic Thiem's run with a 6-3, 6-4 success.