Lando Norris topped first practice for the Spanish Grand Prix ahead of Max Verstappen and Carlos Sainz.
George Russell set the fourth quickest time ahead of Mexican driver Sergio Perez in the opening session of the weekend.
A flurry of cars joined the circuit at the start of the one-hour FP1 session in Spain.
Ollie Bearman headed out onto the track on the medium tyre during his second of six FP1 sessions of the season for Haas.
Yuki Tsunoda set the pace in the opening stages for RB ahead of George Russell and Carlos Sainz, with all of the top seven using the hard tyre.
The times continued to tumble as Russell set a 1:15.868, usurping championship leader Verstappen.
Perez will take a three-place grid drop this weekend after an infringement in Montreal and moved into fourth place.
Verstappen moved ahead of Russell to go quickest in the weekend’s first practice session, two-tenths of a second quicker than the British driver.
McLaren’s Oscar Piastri had a quiet opening 15 minutes and moved into P11 just behind Alex Albon.
Perez had concerns about his throttle pedal and an understeering Red Bull RB20 before his engineer, Hugh Bird, told him it would be discussed in the garage.
Similarly, Charles Leclerc suffered from understeer at Turn 10, reporting that “The car is horrendous for now.”
Norris brushed the gravel on the exit of Turn 12 but managed to continue, lamenting the lack of grip at the rear of his McLaren.
With half an hour to go, Russell switched to the grippier medium tyre and returned to the top of the timesheets before being beaten by Carlos Sainz.
The Spaniard ran Ferrari’s new floor in FP1 while Leclerc used the old one so the Italian team could make a direct comparison.
Both Red Bulls opted for the soft tyre as Verstappen set a 1:14.252, fourth-tenths quicker than teammate Perez on the same tyre.
Verstappen held the quickest time ahead of Sainz, Perez, Russell and Lewis Hamilton in fifth place.
Tsunoda and Russell got close together on the back straight towards Turn 10 but avoided contact.
Norris went fractionally faster than Verstappen to go quickest with 23 minutes to go, setting the fastest first sector of the session.
A small piece of bodywork came off Fernando Alonso’s Aston Martin on the exit of Campsa, causing the red flags to be deployed so the part could be retrieved.
The session resumed with 18 minutes to go at a very hot Circuit De Barcelona-Catalunya.
In the final part of the session, most teams switched to longer runs as Norris continued to set the pace ahead of Verstappen.
Leclerc struggled by his lofty standards, finishing in 11th place, while Bearman ended up in P19 just two-tenths slower than his teammate Kevin Magnussen.
