Mick Schumacher branded his first day back in a Formula 1 car since being dropped by Haas at the end of 2022 as "physical" after logging 152 laps for Mercedes.
The tyre test was the second day of Pirelli's in-season testing for the 2024 compounds, as they evaluate whether they will follow through with a proposed blanket ban for next season.
Schumacher, who became Mercedes' Test and Reserve driver at the start of the season, said it was a productive first day back having spent the last few months in their simulator.
"It was great! I learned a lot and it was a lot of fun," said Schumacher.
"It was a very productive day; we got through everything we wanted to and ran every test tyre on the plan.
"It was also good to have that first experience of the tyres without any blankets. Obviously having not driven in a while, I felt it physically, but it was good to be back in the driving seat."
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Test experience gives Schumacher better understanding
Much of the focus was on tyre work for Pirelli, but Schumacher believes the experience was valuable help in his role as the reserve should he ever need to stand in for Lewis Hamilton or George Russell.
"This experience will definitely benefit me in my role. I have a better understanding of what to look out for and what to work on," he explained.
"I also have a better understanding of all the procedures and how the team works trackside. That would be a key factor in case I ever have to jump in and race."
Even though Mercedes team boss Toto Wolff has ruled out a potential return to the grid for Schumacher in 2024, he is optimistic that opportunities will open up in 2025.