Valtteri Bottas led the way for Mercedes as Formula 1 action resumed on Friday at the Circuit de Barcelona-Catalunya.
Bottas clocked a time of 1:17.951 as teams began preparations for the Spanish Grand Prix, which will potentially be the last to be held at the circuit.
Bottas’ session was interrupted by an oil leak in the closing stages but he nonetheless wound up 0.115s clear of Ferrari’s Sebastian Vettel.
Vettel’s team-mate Charles Leclerc finished third, 0.221s down on Bottas, while fourth-placed Lewis Hamilton had a low-key session, with his best time 0.624s behind the championship leader.
Haas displayed strong pace, as it did pre-season, with Romain Grosjean fifth and Kevin Magnussen seventh, the pair sandwiched by sole local representative of McLaren's Carlos Sainz Jr.
Red Bull had a quiet session as Pierre Gasly and Max Verstappen were only eighth and 12th respectively.
Verstappen spent the final chunk of the session in the garage as Red Bull mechanics worked on addressing a suspected oil leak arising from the power unit.
Daniil Kvyat continued Toro Rosso’s eye-catching one-lap pace by classifying in ninth, with Nico Hulkenberg edging Renault team-mate Daniel Ricciardo to claim the final top 10 spot.
Only Ricciardo, who will take a three-place grid penalty for hitting Kvyat in Azerbaijan, has taken on the updated Renault engine so far.
Lance Stroll was 13th for Racing Point but brought the session to a premature end when he crashed through Turn 9.
“Oh jesus I got the grass on entry,” confirmed Stroll, who caused damage to the left-front of the Racing Point RP19 in the crash.
Williams once more finished at the rear of the pack though Robert Kubica managed to beat George Russell by a tenth of a second, and was within three-tenths of 18th-placed Kimi Raikkonen.
Second practice is scheduled for 15:00 local time.
