Hamilton felt the new W09 seemed a much better auto than last year's "diva", a nickname bestowed on it early on by team boss Toto Wolff for its sometimes twitchy and temperamental behaviour. "Naturally it's an evolution of last year's vehicle and we've got better tires and here we've got a new [Barcelona track] surface, so that might make things seem even better than it really is". Around this time it was also ton up for Pierre Gasly in the Honda-powered Toro Rosso, further indication that Honda might have finally come good. I was really happy to get out today to be honest.
"The last four races last year helped to get to know everyone [at Renault] and to give my feedback regarding last year's auto", he said.
Kevin Magnussen used super-soft tyres to set the fourth fastest time and was just 0.076s shy of Vettel by the end of the day with a total of 92 laps in his Haas.
However, he's only under contract with team for this season.
Sebastian Vettel of Ferrari, last year's runner-up in the drivers' championship, was third-fastest, almost a second behind world champion Hamilton. "You're going through a corner and the auto starts moving a bit more, you have to be a bit more responsive and I like that challenge".
"I'm not quite sure why they do resurface [certain tracks], I think it's a waste of money in general", he said. "It is a long year and a long time from here to the end of the season". The fact he achieved it on medium tyres only made the time more impressive, offering yet another reminder of the quality of the Mercedes vehicles.
"This week we've seen the first glimpse of the Renault R.S.18's potential on track, albeit in very cold, wet and unrepresentative conditions", said Abiteboul. Ferrari will certainly be aiming for consistency as Sergio Marchionne overlooks from the brand's headquarters in his final year at the helm.
The British driver was a half-second faster than Stoffel Vandoorne of McLaren, who had his time on the faster hypersoft tyres.
Acknowledging he enjoys the challenge offered by bumpier circuits, Hamilton described the Barcelona track as now being in its "easiest" state since the start of his F1 career.
There was another red flag when Max Verstappen spun into the gravel on the 12th turn.
McLaren had planned to do its driver switch earlier in the day but despite there being no rain throughout the session, the track took longer to dry after Wednesday's snow and overnight showers.
"Mercedes has been the best team for years now", Bottas said in Barcelona. "I don't like testing but today I actually was really keen to get out, obviously because we hadn't had many laps.to get a feel for the tyres and warm-up process and kind of stretch the legs a little bit on this new vehicle. So reliability was solid and hats off to everyone for that".