Summary Sebastian Vettel dominated opening day of practice ahead of this weekend's United States Grand Prix.
Defending world champion Sebastian Vettel dominated Friday s opening day of practice ahead of this weekend s United States Grand Prix for his Red Bull team as he bids to clinch a third successive title.
Vettel, who was fastest in the morning free practice session ahead of Lewis Hamilton of McLaren, was quickest again in the afternoon ahead of his Red Bull team-mate Mark Webber as the champion team stamped their authority on the action.
The 25-year-old German clocked a best lap of one minute and 37.718 seconds to top the times in the second session to outpace Webber by seven-tenths of a second despite missing much of the afternoon running due to a water leak.
Vettel s only remaining title rival, two-time former champion Fernando Alonso of Ferrari, was third fastest ahead of Hamilton and his McLaren team-mate and fellow-Briton Jenson Button.
Alonso s Ferrari team-mate, Brazilian Felipe Massa, was sixth in the second session run on the green new Circuit of the Americas 25 km outside downtown Austin ahead of Nico Rosberg of Mercedes.
Brazilian Bruno Senna of Williams was eighth fastest ahead of Kamui Kobayashi of Sauber and retirement-bound Michael Schumacher in his Mercedes.
Webber was fastest for most of the afternoon before Vettel s re-emergence late in the session to trim the fastest time of the day as they both proved they have the pace to enjoy Formula One s return to America for the first time in five years.
