Mercedes technical director James Allison does expect the team to start upping their performance after a subdued start to testing.
The world champions are known to run very conservatively in pre-season and have spent all of this week focusing on long-run pace, while rivals Ferrari have been topping the timesheet.
On Wednesday, both Lewis Hamilton and Valtteri Bottas actually finished bottom of the times, except for the new Williams, but amassed a massive 182 laps, the most for any team in a single day so far.
"Both drivers completed trouble-free race distances today and it was another very productive day for us in terms of knowing how hard we can lean on the tyres in these conditions," Allison explained.
"It's all part of building the foundation for the week that will follow and it's good to have those race distances tucked away so early in the test, leaving us able to focus a little bit more on performance tomorrow, but most of that work will come in the following week."
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As for Hamilton, who ran in the morning, he revealed the excitement that comes with getting to know the nuances of every new car.
"We have been digging deep, trying to understand the car, pretty much the same as the beginning of every year," he said.
"I love that challenge of coming back each year; getting into a new car is like meeting someone new - you don't know the good and bad and the journey you go on with that car is a really privileged position.
"It's crazy to think this is my seventh season with the [Mercedes] team, and this looks like it is going to be the most challenging year of our partnership so I'm super excited.
"I love racing so nothing really changes there."
