Sauber has declared Formula Renault 3.5 champion Robin Frijns's first proper Formula 1 test as "a good day".
The Dutchman got his first taste of a 2012 F1 car and Pirelli's race-spec tyres on the opening day of the young-driver test, having previously driven a 2010 Red Bull RB6 on demo tyres at Moscow Raceway earlier this year.
Frijns, who will drive the 2012 Red Bull RB8 on Thursday as a prize for his FR3.5 title, was fourth fastest of the seven drivers in action on Tuesday.
Sauber's head of track engineering Giampaolo Dall'Ara said: "Robin did fine. Physically he coped well and also, for his age, he gave us good feedback.
"The mileage is a lot and the laptime is also good. We started with the hard tyres and did some aero work in the morning before actually working on his laptime.
"Towards the end of the day we gave him an idea of different tyre compounds and went with a set of medium and a set of soft. But we never sent him out with a qualifying fuel level."
Frijns, who could earn himself a long-term deal with Sauber, added that he feels he could have set a faster time.
"There is obviously a lot to learn," said the 21-year-old. "On my fastest lap with soft tyres I made a mistake, so there was more to come.
"In the afternoon I found it hard to understand the tyre compounds. I had only driven on Michelin tyres before, and with the Pirelli compounds it was difficult.
"I had the feeling the more careful I handled them the worse it became."
He also admitted that he had found his first full day of F1 action tiring.
"This was hard work - not in the beginning but then suddenly I felt it, especially from the brakes," he said.
"I am really tired now and know I have to go and exercise more."