BARCELONA, Spain – Carlos Sainz helped keep McLaren on top of the Formula 1 time sheets by posting the fastest lap of testing on Wednesday at Circuit de Barcelona-Catalunya.

Sainz toured the 2.892 mile course in 1:17.144 with his MCL34 to lead the pack, despite an early water-pressure issue during the morning session that disrupted the team’s program briefly before they returned to the track.

“It’s been a good day of work. We managed to do a lot of laps again today, and more or less a full race simulation,” said Sainz. “There are still a few niggles and stoppages that we wish we didn’t have, but every time we go out on track we’re a bit more reliable and we keep moving in the right direction. Overall, I’m happy that we made the most of the time on track today.

“The time sheets still aren’t important. We’re only focused on our run plans and tests, rather than wasting our energy on trying to calculate where we’re at compared to the others. Once we see what everyone else brings in Australia, we’ll be in a better position to compare our performance,” Sainz added. “For the moment, I’ll look back over these six days with my engineers, what I liked and what I didn’t like, and try to put together the best compromise for my last day in the car on Friday.”

Sergio Perez was second for Racing Point F1, seven tenths adrift at 1:17.842, while Ferrari ran into disaster despite Sebastian Vettel posting the third-quickest lap of the day at 1:18.195.

Vettel was working his 41st lap of the morning session when his Ferrari SF90 went off-track and hard into the barriers at turn three, triggering the car’s g-force sensors and requiring Vettel to take a trip to the medical center to be checked out by doctors.

Ferrari later revealed that a mechanical problem caused the crash, but didn’t provide any further details specifying the exact issue.

Kimi Raikkonen was fourth for Alfa Romeo, though his car ground to a halt after the checkered flag, with Romain Grosjean completing the top five for Haas F1.

Max Verstappen, Daniil Kvyat, Valtteri Bottas, Lewis Hamilton and Nico Hulkenberg filled out the remainder of the top 10.