Stan Wawrinka will face Daniil Medvedev in the second round of the Moselle Open after beating Joao Sousa in straight sets.
Wawrinka came through two qualifying matches to take his place in the main draw before defeating Sousa 7-6 (7-1) 6-2 in Metz on Wednesday.
The three-time grand slam champion's victory was only his fourth in a main draw at tour-level this year following a 13-month absence due to a foot injury.
Wawrinka said after setting up a showdown with top seed Medvedev: "It's the first time I won three matches in the same tournament for more than two years, so it's great.
"I'm getting confidence from winning a few matches, so I'm feeling a bit more relaxed, the way I'm moving. I think the level was good from me, and I'm happy with the win."
Dominic Thiem also advanced at the indoor hard-court event, seeing off Richard Gasquet 6-3 7-6 (7-3).
Sebastian Korda was the first man to seal a quarter-final spot, sending third seed Lorenzo Musetti packing with a 6-3 7-6 (8-6) victory in the last match of the day.
Meanwhile, Alexander Bublik, Gregoire Barrere and Benjamin Bonzi were the other first-round winners.