Ferrari’s Charles Leclerc was fastest at the end of an incident-packed first practice session at the Emilia Romagna Grand Prix.
Leclerc, using Ferrari’s first big upgrade of the season, was 0.104 seconds quicker than George Russell’s Mercedes, with the second Ferrari of Carlos Sainz third in Imola.
Championship leader Max Verstappen was fifth in the Red Bull, complaining of a lack of grip, behind team-mate Sergio Perez.
Lando Norris, winner of the last race in Miami for McLaren, was 12th fastest, his team-mate Oscar Piastri in eighth.
RB’s Yuki Tsunoda was sixth, ahead of Mercedes’ Lewis Hamilton.
Leclerc had a smooth session but many of his rivals had incidents to varying degrees.
Sainz ran over the grass after locking a front wheel at the Variante Alta chicane, Hamilton had a spin at Acque Minerali and another off-track moment later on, and Russell rescued a wild moment at Tamburello.
Verstappen, meanwhile, complained that he was struggling in Turns 11 and 12, Acque Minerali, saying he had no grip at that corner because the car was bottoming when he hit the brakes and then lacking front grip on turn-in.
Trying to improve his time later in the session, he was slightly up on Leclerc’s fastest time only to lock his brakes and have a wild trip across the grass at Variante Alta.
Having one last attempt to improve his time, he then ran straight on into the gravel at Acque Minerali.
The Imola track that hosts the race is known as an old-school track - narrow with limited run-off areas - and has also had extra gravel traps added to increase the jeopardy for the drivers.
Many of the leading teams have upgrades for this race.
Ferrari have their first major aerodynamic development of the season, with new bodywork and floor. Red Bull have a new floor and Mercedes and Aston Martin have also brought new parts, while McLaren are continuing the major upgrade they introduced in Miami.