Barcelona testing – Kimi Raikkonen took advantage of a drying track to lead the morning session ahead of Haas driver Romain Grosjean, whilst the Mercedes team encountered electrical issues.
The circuit was doused with water over the course of the night in order to give Pirelli the chance to assess their full wet tyres.
Drivers were hesitant to clock too many miles on the wet surface, with Max Verstappen and Kimi Raikkonen sharing the top spot in the early hours of the day.
However, with the track drying out fairly quickly, Pirelli elected not to send the tanker trucks back out until the afternoon and allow the track to continue to dry out, resulting in the fastest laps constantly being beaten throughout the morning.
Kimi Raikkonen was the first man to set a lap on the slick tyres. Equipped with soft tyres, the Ferrari driver set a 1:25.557 to go several seconds clear of the fastest intermediate-tyre time.
With the track improving, first place was shared between Sergio Perez – who had a delayed start to the morning – and Stoffel Vandoorne, before Raikkonen reclaimed first place with a 1:22.305, enjoying a two-second advantage.
Romain Grosjean set a late lap time on the super soft tyre to go second fastest, 0.434 short of Raikkonen’s time, and ahead of McLaren’s Stoffel Vandoorne, who registered a late lap on the ultra-soft tyre.
Max Verstappen’s medium-compound tyre lap ended up being the fourth-fastest time, ahead of Sergio Perez, Nico Hulkenberg and Antonio Giovinazzi.
Despite Lewis Hamilton being scheduled to run in the morning, an electronics issues prevented the Mercedes from running for most of the session.
However, Valtteri Bottas was sent out in the final few minutes to check over the car, clocking nine laps, but with no fast laps being set.
Daniil Kvyat could only complete one lap all morning after the Toro Rosso team encountered a technical problem, resulting in a power unit change.
Finally, Williams elected not to run at all. Yesterday’s crash resulted in chassis damage on the FW40,causing Williams to pull out of the final days testing.