Mathieu ousted Donald Young 6-0, 6-1. He won 63 percent of the points when serving and 64 percent off Young's serve. Mathieu lost just five points when Young was serving in the first set.
No. 13-seeded Fernando Verdasco got by Olivier Rochus 4-6, 6-3, 7-5. Verdasco didn't face a break point after the first set.
Jurgen Melzer, the 15th seed, defeated Lukasz Kubot 6-2, 7-5 behind five service breaks and No. 16 Alexandr Dolgopolov swept past Juan Ignacio Chela 6-2, 6-2 in 58 minutes.
Bernard Tomic stopped Denis Istomin 6-4, 6-3; Julien Benneteau defeated Marcel Granollers 6-3, 3-6, 6-2; and Albert Montanes eliminated Milos Raonic 6-2, 3-6, 6-3. Philipp Kohlschreiber was a 6-4, 6-4 winner over Rufin Guillaume and Jarkko Nieminen edged past Radek Stepanek 6-3, 7-6 (7-3) in other first-round matches.
The top nine seeds, including world No. 1 Novak Djokovic and seven-time defending champion Rafael Nadal, were given first-round byes. Seven of the Top 10-ranked players are in the draw this week.