Gilles Simon marked his return to action after more than a month out with a 6-2 6-3 victory over fellow Frenchman Kenny de Schepper at the ATP Moselle Open.
The second seed, who missed the US Open in New York due to a hip injury, needed 65 minutes to complete a routine straight sets triumph and set up a quarter-final showdown with American Sam Querrey.
Simon raced into a 4-0 lead in the opening set but had to wait until the seventh game to register a break of serve in the second.
"Today was a great match," he told ATPworldtour.com afterwards. "I returned very well and was relaxed on court. I was playing just point after point and felt very well."
Nicolas Mahut is also through to the last eight in Metz after he upset third-seeded Italian Andreas Seppi 6-4 6-4 in the second round.
A pair of breaks in each set proved enough for the 31-year-old to knock out last year's beaten finalist.
Mahut will next face Benjamin Becker, the German having battled back from a set down to see off French wild card Albano Olivetti 6-7 (8-10) 6-3 6-1.
The news was not so good for Becker's compatriot Philipp Kohlschreiber, the fourth seed being forced to retire when 2-1 down in the deciding set against Carlos Berlocq of Argentina.
Florian Mayer, another German in the draw, did at least advance thanks to a 6-3 6-2 result against Lukas Lacko that saw the duo on court for exactly an hour.
Top seed Jo-Wilfried Tsonga of France will go up against Tobias Kamke of Germany in the quarter-finals.