Russian Karen Khachanov surprised French third seed Lucas Pouille 7-5 3-6 7-5 in Marseille to win his second ATP title.
The 21-year-old ninth seed, who won his maiden title at Chengdu in 2016, took victory in just under two hours.
The world number 47 broke at the end of the first set to lead, before world number 16 Pouille saved two break points in the second set to level.
But Khachanov served nine aces in the final set to edge out Pouille.