Carlos Sainz edged out Ferrari team mate Charles Leclerc to the fastest time in rain-disrupted opening practice for the Belgian Grand Prix, the first track action since F1 returned from its summer break.

The Spaniard clocked a 1m 46.538s on the softs to finish 0.069s clear of Leclerc, who will start towards the back of the grid after Ferrari made engine component changes that exceed his allocation.

Championship leader Max Verstappen was third quickest, with the Mercedes of George Russell fourth and Aston Martin’s Lance Stroll fifth.

Intermediates were the tyres of choice when the session got going for installation laps, with persistent light rain peppering Spa throughout the morning. But conditions improved quickly to the point that slicks were soon bolted on.

Verstappen, who will also start towards the back of the grid after Red Bull fitted a suite of new engine components to trigger engine penalties, was the early pace-setter. But he was usurped by the Ferrari duo.

But with 20 minutes to go, the session was red flagged after Kevin Magnussen was told to stop his Haas on track, on the hill down to Eau Rouge-Raidillon. Haas boss Guenther Steiner suggested it was a high voltage issue.

While the session got going again, an incoming rain shower meant no one else could improve.

Alex Albon was sixth, ahead of Daniel Ricciardo – who will leave McLaren at the end of the season after mutually agreeing with the team to end his contract early.

AlphaTauri’s Yuki Tsunoda was eighth, with Liam Lawson – borrowing the second car for FP1 in place of Pierre Gasly for his first race weekend running, as part of the rules that dictate that all teams must run young drivers for at least two practice sessions – 19th.