Lewis Hamilton sets ominous early pace in Austin

Hamilton on the verge of fourth title (1:04)

Jennie Gow reports from Austin ahead of the race that could seal Lewis Hamilton's fourth drivers' championship. (1:04)

AUSTIN -- Lewis Hamilton put down an immediate marker to his U.S. Grand Prix rivals with a time half a second quicker than Sebastian Vettel in opening practice.

Hamilton has an outside shot of securing a fourth world championship this weekend if he out-scores Vettel by 15 points. The Englishman is heavily favoured to take the race victory, at least: he has won all but one of the races held at the Circuit of the Americas since it joined the F1 calendar in 2012, while Mercedes has excelled in Austin since the introduction of V6 turbos two years later.

In an FP1 session that started with light drizzle, the final 40 minutes saw the majority of slick tyre running as the circuit dried out. Hamilton's best attempt on the super-soft tyres was a 1:36.335, though the pace of all 20 drivers is likely to come down as the weekend progresses and the track evolves.

Vettel managed to split the Mercedes of Hamilton and Valtteri Bottas but still found himself 0.593s behind his championship rival. Bottas' session was compromised massively by a big lock-up at Turn 1, which left him experiencing big vibrations in the car. The incident cost him a lot of time and he completed just 10 laps.

Speculation coming into the weekend suggested Red Bull could pose a threat to Ferrari but the Milton Keynes team was 0.4s off the pace in the opening session, with Max Verstappen -- now holding a freshly-inked contract extension for 2020 -- grabbing fourth place.

A late ultra-soft lap from Stoffel Vandoorne saw him climb to fifth, 0.2s ahead of Felipe Massa. Ferrari's Kimi Raikkonen was seventh, though his quickest time was set on the super-soft tyre. Esteban Ocon and Sergio Perez claimed eighth and ninth, 1.4s off the pace despite setting their best laps on the soft compound, which is the slowest of the three tyre types on offer.

Meanwhile Carlos Sainz made an impressive start to life with Renault, rounding out the top ten but, more significantly, beating New teammate Nico Hulkenberg by 0.6s. It is early in the weekend to jump to conclusions about that pace, especially as Hulkenberg did not appear to execute a clean flying lap, but Sainz's solid start will be encouraging for Renault after spending 16 races with Hulkenberg comprehensively out-performing Jolyon Palmer.

Brendon Hartley's first taste of a 2017 car saw him finish 14th for Toro Rosso. The New Zealander has been handed a shock debut ahead of this weekend's race and, other than simulator work this week, admitted during his Thursday media sessions that he was unprepared to drive the car given the limited time since the announcement. Hartley is facing the prospect of starting from last due to engine penalties, though that might allow him and Toro Rosso to focus primarily on race set-up.

Romain Grosjean, sporting a tribute helmet to Moto GP rider Nicky Hayden, who was killed in a road accident this year, finished 15th. Daniel Ricciardo could only manage 16th for Red Bull as he completed the third-fewest laps of anyone (14), though team boss Christian Horner later told Sky Sports the Australian was simply experimenting with different set-ups.

Sean Gelael, in for Kvyat in the session, finished 17th, but 1.2s off Hartley -- who, before FP1, had not driven an F1 car since 2011. Sauber pair Marcus Ericsson and newly-crowned F2 champion Charles Leclerc -- in for Pascal Wehrlein for FP1 -- finished 18th and 19th.

Fernando Alonso came into the weekend with a new McLaren contract but he had a frustrating morning as he was limited to just four laps as the team encountered a hydraulic problem.