Carlos Sainz kept McLaren at the top of the timesheets as a nasty crash for Sebastian Vettel disrupted the Day 2 morning session in Barcelona,

The German went off into the barrier at the high-speed Turn 3 just over halfway through the four hours of running, causing a 40-minute red flag as his car was carefully recovered.

Ferrari has confirmed a mechanical issue caused the incident with trackside spectators suggesting a problem at the front-left of the SF90 could be seen.

Vettel was taken to the medical centre for checks but all indications are the four-time world champion is unharmed having walked away.

It did mean, however, all teams had to alter their morning programs, but Sainz went out early on the red-marked C4 tyres to post the best time of pre-season so far, a 1m17.144s.

Despite the crash, Vettel's best time remained good enough for second, narrowly ahead of Max Verstappen in the Red Bull who did cause a very brief red flag having stalled at the end of the pit-lane.

Mercedes was hoping to conduct back-to-back aero tests on their new upgrades, after missing out on Tuesday afternoon due to an engine change.

Though the red flags didn't help, Valtteri Bottas did manage to complete the most laps with 75 as he finished fourth, joining Ferrari and Red Bull in the 1m18's on the C3 Pirelli compound.

Daniil Kvyat and Kimi Raikkonen followed in fifth and sixth, ahead of Sergio Perez, who only managed 29 laps in the Racing Point, the fewest of any driver.

Williams continue to make progress as Robert Kubica was eighth thanks to some late improvement on the C4 tyres, just ahead of Romain Grosjean's Haas. 

Finally, Daniel Ricciardo brought up the standings by some margin in the Renault as the Australian concentrated on longer runs during his stints on track, finishing just behind Bottas with 72 laps to his name. 

A full look at the morning standings can be seen below: