Hamilton quickest in wet/dry FP1 at Austin
20 October 2017 – Mercedes' Lewis Hamilton set the quickest time during the opening 90-minute session at a drizzly Circuit of the Americas, ahead of championship rival Sebastian Vettel and team-mate Valtteri Bottas.
Light rain prior to the start of the session left the circuit damp, and drivers took to the track on Intermediates, with some using the 2017-spec rubber, and others trialling Pirelli's prototype compound.
Red Bull's Max Verstappen led the way before conditions improved approaching the mid-point of the session, enabling Vettel to switch to Super Softs.
Vettel, despite a tardy final sector, edged clear, though was demoted by Daniel Ricciardo after a brief mid-session lull, as the Australian put his Red Bull on top.
Verstappen enjoyed another brief spell up front before Hamilton surged clear, consequently improving on his next run, to leave him with a 1:36.335.
Hamilton's effort was over half a second faster than Vettel, while Bottas was third, via a hefty lock-up into Turn 1, which flat-spotted both front tyres.
Verstappen, renewed at Red Bull through 2020, wound up fourth, as the leading quartet all clocked their best efforts on the Super Soft compound.
Stoffel Vandoorne ran the Ultra Softs and went fifth, ahead of Williams' Felipe Massa, Ferrari's Kimi Räikkönen, and the Force India pair of Esteban Ocon and Sergio Pérez, who used Softs for their best laps.
Carlos Sainz Jr. got up to speed in his new surroundings at Renault and rounded out the top 10, in front of Kevin Magnussen, Lance Stroll and team-mate Nico Hülkenberg.
Debutant Brendon Hartley, already facing a substantial grid penalty due to power unit changes, dorve Formula 1 machinery for the first time in five years and finished 14th, as he took a measured approach.
Romain Grosjean was 15th, while Ricciardo did not improve on his initial slick-shod sequence of laps and was shuffled down to an unrepresentative 16th position.
Sean Gelael had a couple of off-track excursions as he had another outing with Toro Rosso, while Marcus Ericsson and Charles Leclerc took 18th and 19th for Sauber.
Fernando Alonso's session was compromised by a hydraulic problem, though he appeared during the final 10 minutes for an installation lap.
Friday's second 90-minute practice session will begin at 14:00 local time