Formula One championship leader Lewis Hamilton posted the fastest time in Friday's first practice for the U.S. Grand Prix, edging Mercedes teammate and title rival Nico Rosberg.
Hamilton's fastest lap at the Circuit of the Americas was 1 minute, 39.941 seconds. Rosberg was 0.292 seconds behind. McLaren's Jenson Button was third.
Hamilton is chasing his second world championship. He won the title in 2008 with McLaren and has a 17-point lead over Rosberg with 100 still available in the final three races. The final race in Abu Dhabi will be worth double points, a new system that Hamilton this week questioned as an unfair way to wrap a season-long dual between himself and Rosberg.
Hamilton won in Austin in 2012 and he has eight wins this season.