"I just tried to put the ball inside. Nothing more,'' the Frenchman said. "I don't know why I lost the second set and won the third set 6-love.''
Also advancing was Germany's Tommy Haas, the fifth seed. He used an accurate service game to sweep American John Isner 6-3, 6-4.
Isner won just 5-of-27 of Haas' first serves and 5-of-26 second serves.
"My second serve was very good today,'' Haas said. "I used that to move him around a bit.
"I was glad to get a break early. You want to try to get a good start, because once he gets up in breaks and gets relaxed with his serve, he's tough.''
Third-seeded Dmitry Tursunov of Russia, the defending champion, advanced to the quarterfinal round when his opponent, American Wayne Odesnik, withdrew with a back injury before the night's final match.
Earlier, Paul Capdeville of Chile won 23 of his 27 of his first-serve points and swept qualifier Joseph Sirianni of Australia, 6-3, 6-4.
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