Charles Leclerc led Ferrari teammate Carlos Sainz to the top of the time sheet in first practice at the Spanish Grand Prix.

Title leader Leclerc’s best time of 1m19.828s was 0.079s quicker than his teammate’s fastest attempt despite the Monegasque complaining of light traffic on his flying lap on softs.

Both Ferrari cars are running in heavily upgraded configuration for the first time this season, with the floor being the principal area of focus as the team seeks to close its estimated 0.2s gap to Red Bull Racing.

Max Verstappen followed in third in his RB18 — which was sporting some weight-saving and other updates of its own — at 0.336s off the pace, though the Dutchman was on track to go fastest before encountering traffic in the last sector.

George Russell was the quickest Mercedes in the first session on what the Briton has described as a crucial weekend for the team and its troubled car.

The W13 has received upgrades this weekend, and the team is cautiously optimistic that it has moved the car a step forward, with neither Russell nor Lewis Hamilton experiencing much of the bouncing that’s so afflicted them this season — although the same was true during practice at the Miami Grand Prix before the porpoising returned with a vengeance on Saturday.

Russell was 0.762s off the pace, while Hamilton a further 0.2s back in sixth after suffering a DRS problem on his flying lap. Fernando Alonso split the pair for Alpine, but the Spaniard will see the stewards after the session for impeding Hamilton in the final sector.

McLaren and AlphaTauri shared the lower reaches of the top 10, with Lando Norris leading Pierre Gasly in seventh and eighth ahead of Daniel Ricciardo and Yuki Tsunoda in ninth and 10th.

Esteban Ocon was 11th in the second Alpine ahead of Lance Stroll, whose upgraded Red Bull Racing-like Aston Martin had drawn controversy but, on the basis of early evidence, gathered only limited additional pace.

Alfa Romeo test driver Robert Kubica piloted Zhou Guanyu’s car to 13th as part of the team’s mission to evaluate its updates.

Haas teammates Kevin Magnussen and Mick Schumacher were 14th and 15th ahead of Sebastian Vettel and Valtteri Bottas.

Nyck de Vries got his first taste of Formula 1 on a live weekend in Alex Albon’s Williams. The reigning Mercedes Formula E champion acquitted himself well in 18th and around 0.1s quicker than established teammate Nicholas Latifi in 19th. The Dutchman, whose running in this session partly satisfies the requirement for each team to devote two practice sessions to rookie drivers, completed a session-equaling 28 laps in the hour-long session.

Juri Vips, the Red Bull Racing reserve driver substituting Sergio Perez for first practice, also got his first taste of a Formula 1 weekend in Spain. The Estonian propped up the table and will have to see the stewards after the session for impeding George Russell.