Benoit Paire is through to the second round of the Sofia Open following a 6-4 7-5 win over seventh seed Alejandro Davidovich Fokina.
The Frenchman - ranked no. 49 in the world - marked his debut at the ATP 250 event by ending a three-match losing run, progressing after one hour and 37 minutes on court.
Paire, who recorded five breaks of serve en route to victory, will be up against either James Duckworth or Emil Ruusuvuori next.
"[I am] happy about the win," Paire said in his on-court interview. "It was not easy. Alejandro is a very good player, so I had to be focused on my game.
"I had to serve well and do my best and that is what I did and I am very happy and proud of my game today.
"I played well in the first game, it was good for my confidence. The most important thing is to stay on my game and stay focused. I was solid today so I am very happy."
Also in Monday's action, Adrian Mannarino was another seed to suffer an early exit, going down in straight sets to Gianluca Mager.
Miomir Kecmanovic came through a tight two-set contest to knock out Adrian Andreev, including taking the opener via a tie-break.