Japanese Grand Prix – Sebastian Vettel led championship leader Lewis Hamilton by 0.211s in a red-flagged FP1 at Suzuka.
Having escaped the threat of a gearbox penalty following his post-race collision with Lance Stroll in Malaysia, Vettel did a time of 1:29.166 on the supersoft tyre, just two tenths of a second shy of the ultimate lap record set by Michael Schumacher in 2006.
Hamilton was running the new Mercedes aero kit, which the team confirmed prior to the session both drivers would be running this weekend.
The session was interrupted by a crash for Carlos Sainz Jr, who lost the back end of his Toro Rosso on the kerbing on the exit of the hairpin. He was pitched nose-first into the tyre barriers, leaving debris strewn across the track.
Sainz is already expected to take a 20-place grid penalty for taking on a sixth MGU-H and a fifth internal combustion engine and turbo charger.
He finished the session 17th fastest ahead of rookie team mate Pierre Gasly.
Daniel Ricciardo was third fastest by 0.375s for Red Bull, ahead of Kimi Raikkonen, Valtteri Bottas and Max Verstappen.
On-track action was hastened as rain lingered in the air throughout the session, with most teams making an early start to their race simulations as heavier rain is expected for FP2.
Esteban Ocon was seventh fastest for Force India, ahead of Renault’s Nico Hulkenberg and Haas’ Romain Grosjean. Stoffel Vandoorne completed the top ten for McLaren.
Kevin Magnussen suffered a water pressure issue early in the session. A fix from the Haas mechanics meant he could compete in most of the session before the problem re-occurred towards the end of FP1.