Like its main rivals, Mercedes enjoyed a trouble-free opening day of testing in Barcelona on Wednesday, a smooth session that surprised the reigning world champions.
George Russell and Lewis Hamilton racked up a total of 127 laps at the Circuit de Catalunya, with the two drivers clocking in respectively P4 and P5 at the end of Wednesday's running.
Mercedes trackside engineering director Andrew Shovlin had little to say about the W13's performance after a session entirely devoted to data acquisition and set-up work.
But the Briton did admit to being impressed with the remarkable reliability displayed by teams up and down the pitlane that contributed to the day's smooth running.
"We got through a lot of work today and both drivers have been able to give us their initial impressions of the W13," said Shovlin.
"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."
Addressing the relative performance and pace of Mercedes' new-spec car, Shovlin said that it was "too early to say where anyone stands", but the Briton was nevertheless left with a positive feeling at the end of the day.
"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," he said.
"However, our overall feeling from today is a good one and we're looking forward to making more progress tomorrow."
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