Michael Llodra beat David Goffin of Belgium 6-2, 6-4 to reach the second round of the Open 13 and set up a rematch of last year's final against defending champion Juan Martin del Potro.
Ernests Gulbis of Latvia also faces a tough test against top-seeded Tomas Berdych after comfortably seeing off Finland's Jarkko Nieminen 6-3, 6-2.
Hiowever, fifth-seeded Richard Gasquet was upset by Gilles Muller of Luxembourg, losing 2-6, 6-4, 7-6 (5).
The Frenchman, who beat countryman Benoit Paire in the Open Sud de France last week, was leading 5-2 in the final set.
"I was catastrophic at 5-2," Gasquet said. "I did so many errors. I was a bit tired but I wanted to do really well. But it wasn't my day. The umpire was awful, I was awful, everyone was awful."
India's Somdev Devvarman also pulled off an upset as he beat Paire 7-6 (6), 6-7 (7), 6-4. He will next face Bernard Tomic of Australia.
Paire is ranked 339 places above Devvarman.
Fellow Frenchman Gael Monfils also lost, 6-4, 6-4 to Marcel Granollers of Spain.
Meanwhile, Nikolay Davydenko beat Sergiy Stakhovsky 6-2, 4-6, 6-2, and Roberto Bautista-Agut defeated Filip Krajinovic 4-6, 7-6 (5), 6-0.