Federer, ranked No. 1 in the world, has won eight titles already this year, including Wimbledon. He is 61-3 -- 35-1 on hardcourts.
Lleyton Hewitt, Marat Safin and Andy Roddick also advanced.
Hewitt, the third-seeded player from Australia, beat Mario Ancic of Croatia 6-1, 6-4. Fourth-seeded Safin of Russia beat Dominik Hrbaty of Slovakia 6-0, 6-3.
No. 5 Roddick downed Juan Ignacio Chela of Argentina 7-6 (4), 6-2, again unleashing his big serve to win a tiebreaker.
He also did that Wednesday night against Spaniard Juan Carlos Ferrero.
Roddick's match was suspended for 44 minutes because of rain. After the delay, each player held serve twice to reach 6-6.
Roddick used a 145-mph ace to go ahead 5-4 in the tiebreaker, then got Chela to hit wide on the next two points.
Roddick broke Chela in the third game and seventh games of the second set.
The American served 14 aces, but none approached the tiebreaker serve or the two similar ones in the mid-140mph range he used to help win a tiebreaker Wednesday.
"I think a lot of it has to do with Adrenalin," Roddick said.
But he acknowledged that he was trying to be more aggressive in his matches.
In other matches, sixth-seeded Nikolay Davydenko of Russia beat Fernando Gonzalez of Chile 6-3, 6-4; Mikhail Youzhny of Russia beat Gael Monfils of France 4-6, 6-1, 6-1, and Robby Ginepri of the US beat Carlos Moya of Spain 6-3, 6-4.
RSS