Sergiy Stakhovsky will face top seed Gael Monfils in the second round of the Open 13 after ousting Jiri Vesely in straight sets on Tuesday.
Stakhovsky is ranked 52 places below Vesely, but the qualifier from Ukraine needed just 65 minutes to wrap up a 6-2 6-4 victory in Marseille.
Vesely was unable to break the determined world number 107, who failed to qualify at the Rotterdam Open last week but is now eyeing an upset against Monfils in his homeland.
Stakhovsky's compatriot Illya Marchenko will also face a home favourite in the form of second seed Jo-Wilfried Tsonga in round two after he dumped out Andrey Rublev 6-1 7-6 (8-6).
Tsonga ended a two-year wait for a title in Rotterdam last weekend and should be too strong for Marchenko, who took half of his eight break-point opportunities and saved a set point in the tie-break to go through.
Fifth seed Alexander Zverev lost in the first round for the second successive week, going down 7-6 (7-5) 7-6 (7-5) to Nicolas Mahut.
Richard Gasquet, seeded six, dumped out Robin Haase, while Jan-Lennard Struff, Aljaz Bedene, Norbert Gombos and Julien Benneteau came through their first-round matches.