METZ, France -- Nicolas Mahut of France upset third-seeded Andreas Seppi of Italy 6-4, 6-4 to reach the Moselle Open quarterfinals on Thursday.
Frenchman Gilles Simon, Carlos Berlocq of Argentina and German duo Florian Mayer and Benjamin Becker also advanced to the last eight.
The second-seeded Simon cruised past compatriot Kenny De Schepper 6-2, 6-3, while Berlocq was leading 6-7 (7), 7-6 (5), 2-1 when fourth-seeded Philipp Kohlschreiber of Germany retired. Becker outlasted French wild card Albano Olivetti 6-7 (8), 6-3, 6-1, and eighth-seeded Mayer routed Lukas Lacko of Slovakia 6-3, 6-2.
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.
Mahut will face Becker, who lost the first set against Olivetti despite leading 6-2 in the tiebreaker. The German broke Olivetti twice in the next set to even the match and took leads of 3-0 and 5-1 in the third set.
Simon, a 2010 champion, jumped to 4-0 in the opening set. 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 victory when De Schepper's forehand went wide.
Simon will meet Sam Querrey of the United States.
Mayer did not face any break points against Lacko and will play Berlocq in the next round.
The last quarterfinal will pit top-seeded Jo-Wilfried Tsonga of France against Tobias Kamke of Germany.