Top-seeded Daniil Medvedev overcame a poor start to beat Jannik Sinner 1-6, 6-1, 6-2 and reach the Open 13 quarterfinals on Thursday.
The U.S. Open runner-up, who lost in the fourth round of the Australian Open last month, dropped his serve twice but broke the 18-year-old Italian's serve four times at the indoor tournament in Marseille.
The fifth-ranked Medvedev, who had seven aces, next faces French veteran Gilles Simon — who won their two previous meetings. Simon advanced with a 7-6 (6), 6-4 win against Aljaž Bedene.
Also Thursday, fourth-seeded Denis Shapovalov hit 17 aces in a 6-4, 4-6, 6-2 win against hard-hitting Croat Marin Čilić. The 20-year-old Canadian next plays Alexander Bublik.
In later matches, 19-year-old Canadian Felix Auger-Aliassime — seeded seventh — was facing Frenchman Pierre Hugues-Herbert. No. 3 David Goffin played qualifier Egor Gerasimov.