Nicolas Mahut of France upset third-seeded Andreas Seppi of Italy 6-4, 6-4 Thursday to reach the Moselle Open quarterfinals.
Mahut broke last year's runner-up twice in each set. The Frenchman won two titles in the summer and is enjoying his best season.
Frenchman Gilles Simon and German duo Florian Mayer and Benjamin Becker also advanced to the last eight.
The second-seeded Simon cruised past Kenny De Schepper 6-2, 6-3, while the eighth-seeded Mayer did not face a break point in his 6-3, 6-2 victory over Lukas Lacko of Slovakia. Becker outlasted French wild card Albano Olivetti 6-7 (8), 6-3, 6-1.
Simon, a 2010 champion, took a 4-0. De Schepper raised his game in the second set but failed to convert two break points. Simon broke serve for a 4-3 lead before clinching the win when De Schepper's forehand went wide.
Ranked 254th in the world, Olivetti rallied from 6-2 down in the tiebreaker to win the opening set. But Becker broke Olivetti twice in the next set to even the match. The German took leads of 3-0 and 5-1 in the third set.