Mercedes have described the start to pre-season testing as "surprisingly straightforward" after an incident-free day at the Circuit de Barcelona-Catalunya.
Eight of F1's 10 teams comfortably cleared a race distance at the Spanish Grand Prix venue on Wednesday, with Ferrari (153 laps), Red Bull (147 laps) and Williams (132 laps) doubling up.
Their efforts were helped by a trouble-free day of running, with no red flags recorded – Lando Norris' stoppage at the end of the pit lane and Max Verstappen's trip through the gravel the only incidents of note.
Mercedes were next on the mileage charts with 127 laps completed, as they split their running between George Russell and Lewis Hamilton, who wound up fourth and fifth respectively.
Mercedes focused on getting miles under their belt
Andrew Shovlin, Trackside Engineering Director at Mercedes, welcomed the smooth start to proceedings as the F1 field attempt to get to grips with the sport's overhauled technical regulations.
"We got through a lot of work today and both drivers have been able to give us their initial impressions of the W13," he said.
"Overall, the day has been surprisingly straightforward, although looking up and down the pit lane, you can see how high the reliability standards are and most teams seemed to be running their programmes without issue.
"There really is a lot to try and cram into the six days of winter testing when you consider how different the car and the regulations are.
"Nevertheless, we have made good progress on understanding the aerodynamics and the tyres, while at the same time getting nearly 600km under our belts."
"It's too early to say where anyone stands"
As for performance, Shovlin explained that Mercedes will not be looking to get faster lap times on the board until they have ironed out "a few wrinkles" with the W13.
"From a pace point of view, it's too early to say where anyone stands," added Shovlin.
"We've also got a few wrinkles to iron out in terms of balance and performance before really trying to put times on the board.
"However, our overall feeling from today is a good one and we're looking forward to making more progress tomorrow."
Mercedes have yet to confirm their driver run plan for the second day of testing.
Video: Are Mercedes playing it safe with the W13 reveal?
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