Valtteri Bottas and Lewis Hamilton gave Mercedes a combined 182 laps worth of mileage on Wednesday as the German squad continued its substantive work on its W10.
Both drivers ran through their respective programmes without any issues but also without ever chasing for a representative lap time.
Mercedes technical chief James Allison said the team's workload on Wednesday was all about tyre discovery and establishing a baseline for moving forward.
"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," said Allison.
"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."
For Hamilton, it was another day of searching and finding as the W10 Silver Arrow slowly begins to reveal its inner secrets.
"We have been digging deep, trying to understand the car, pretty much the same as the beginning of every year," said the reigning world champion.
"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 real privileged position.
"It's crazy to think this is my seventh season with the 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."
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