Championship leader Lewis Hamilton topped a rain-affected opening practice session ahead of the Sunday’s US Grand Prix at the Circuit of the Americas.
Hamilton set a 1m36.335s, beating rival Sebastian Vettel by over half a second. His Mercedes team-mate Valtteri Bottas completed the top three.
Track conditions were slippery at the start of the session, with drivers opting for the intermediate tyres. Max Verstappen was the early pacesetter on the drying track.
Multiple drivers were caught out in the difficult conditions including Daniel Ricciardo and Sean Gelael, who spun on the damp kerb on the exit of Turn 15. The Indonesian also had an off-track excursion with just seconds remaining, this time at the penultimate corner.
Gelael took Daniil Kvyat’s car for the session while Brendon Hartley made his F1 bow, setting the 14th quickest time; over a second faster than Gelael in the sister Toro Rosso.
Bottas suffered a major lock-up at the first corner, his tyres were so badly flat-spotted, he was forced to pit for a new set.
He still managed to go out and set the third fastest time, Verstappen was fourth with Stoffel Vandoorne fifth for McLaren, just over a second off pacesetter Hamilton.
Felipe Massa was sixth quickest ahead of his former team-mate Kimi Raikkonen. Massa is under investigation for using tyres for three seconds too long.
The Force India duo set their fastest times on the soft tyres, with Esteban Ocon and Sergio Perez eighth and ninth fastest.
On his debut for Renault, Carlos Sainz Jr. was tenth fastest ahead of Kevin Magnussen and Lance Stroll.
Charles Leclerc took Pascal Wehrlein’s Sauber seat for the session, the Formula 2 champion was 19th quickest at the flag, just over three-tenths off regular Marcus Ericsson.
Fernando Alonso spent the majority of the practice session in the garage with mechanical woes.
