This final day of testing in this first week kicked off with continued welcoming weather in Spain. Teams were therefore again eager to get out on track and get the day going, all aiming for another high-mileage day.
After a serene first day of testing for all the teams, Thursday saw a few bumps in the road. There were electrical issues at both Mercedes and Williams, as well as the mechanical problem that stopped Raikkonen's Alfa.
But it was Haas who required the first rebuild, after Romain Grosjean rather blotted his copybook with this off at Turn 4.
Today kicked off with most drivers running aero rakes, including Sebastian Vettel who is enjoying his first morning run now, after having completed on Thursday afternoon and skipped Wednesday. Even after his first taste of the car yesterday, he described the car as a 'step up' from last year after his first foray in the cockpit yesterday, but the Scuderia certainly haven't been lighting up the timing sheets here like they did this time last year...
Vettel and Kvyat became the first drivers to set lap times, even though both with aero equipment fitted on their cars, so not exactly focusing on performance runs.
It was only when Mercedes got up to speed that times further improved, with Bottas going fastest so far with a 1:16.674 on medium tyres, a comfortable 0.3s faster than what Raikkonen managed the day before on softs.
Bottas's time further indicates how the cars seem to be considerably faster than last year. Esteban Ocon, who sat 4th faster after the first two hours of running already stated earlier this week that he felt they were going to improve upon several lap records this season.
When the Finn subsequently fitted softer C5 Pirelli tyres, he went even faster, raising the bar to 1:15.732 and alarming competitors that Mercedes is already in really good shape to start the new Formula One season.
Meanwhile, Ferrari's Sebastian Vettel and Williams' Nicholas Latifi caused session stoppages as their cars halted out on track. They weren't seen afterwards before noon, leaving them both with the least amount of laps completed in the first four hours of running.
Midway, the times looked as follows:
The afternoon session was again about getting mileage in the cars. Switching back from the soft tyre runs before the lunch break, the afternoon kicked off with runs on medium and hard tyres.
That plan was soon ruined, or at least interrupted when Kevin Magnussen slid his car sideways into the barriers at 14:29. The Dane got a swapper on at the exit of Turn 7, spinning into the opposite gravel trap and lightly touching the wall. Easily done on cold tyres. Haas announced half an hour later that they were done with testing for the day, instead focusing on next week.
When the session was restarted 15 minutes later, it was suddenly time for soft tyres for Hamilton. Vettel, Giovinazzi and Gasly joined him out on track. Hamilton ended up slightly slower than his team mate, then returned to the pits to get back for other test work with harder tyres.
After Giovinazzi became the first to cross the 100 lap marker, there was little of note until Renault's Daniel Ricciardo stopped at 16:43. The Australian was doing a long run on Pirelli's C2 tyres before coming to a halt. It took around 15 minutes to get the car back to the pits, leaving an hour of running for the others to get something more out of the first week of testing.
Nicholas Latifi was one of them. Williams completed the engine change on the FW43 and got their driver back out again for an extra few laps.
As the curtain fell at 18:00, it is clear that Ferrari is quite a bit behind the Mercedes and Red Bulls. Racing Point can be happy. McLaren is running fine too while the Renault seems a bit fragile. Next week should reveal more.