Ferrari’s Charles Leclerc headed Red Bull’s Max Verstappen in practice at the Miami Grand Prix.
Leclerc was 0.164 seconds clear of Verstappen, with McLaren’s Oscar Piastri third fastest ahead of Ferrari’s Lewis Hamilton as the season resumed following a five-week break.
Mercedes, who have won the first three races of the season, had a troubled session.
George Russell had a turbo problem early on, which was fixed by a reset in the garage, and could manage only the sixth-fastest time, 0.790secs slower than Leclerc.
He was one place behind team-mate and championship leader Kimi Antonelli, who did not get a chance to run on the soft tyres at the end of the session because Mercedes were investigating an engine problem on his car.