There were nine seeds in action in the men's draw Wednesday and all of them won, including No. 3 Rafael Nadal and No. 6 Juan Martin del Potro.
In the tournament's first three days, the highest seeded player on the men's side to lose has been No. 19 Stanislaus Wawrinka.
Federer, playing a night match at the National Tennis Center's Arthur Ashe Stadium, downed Gruel 6-3, 7-5, 7-5. That moved Federer into the third round, where he will take on Lleyton Hewitt.
Hewitt, seeded 31st, ousted Juan Ignacio Chela 6-3, 6-3, 6-4.
The third-seeded Nadal, playing in his first major championship since falling to Federer in the French Open final, breezed by Richard Gasquet in their first-round match 6-2, 6-2, 6-3.
Del Potro, seeded sixth, blasted Juan Monaco 6-3, 6-3, 6-1.
In other first-round action, No. 9 Gilles Simon defeated Daniel Gimeno-Traver 6-4, 7-6 (7-3), 6-3; 18th-seeded David Ferrer got past Alberto Martin 7-5, 5-7, 6-3, 6-3; No. 13 Gael Monfils won over Jeremy Chardy 6-1, 6-4, 6-3; No. 24 Juan Carlos Ferrero was a 6-4, 6-3, 6-3 winner over Fabrice Santoro; and No. 32 Nicolas Almagro outlasted Steve Darcis 6-2, 6-4, 2-6, 7-6 (10-8).