Jean-Eric Vergne described his first Formula 1 test with Toro Rosso as a "really good experience" and said he was surprised by how much the team was able to achieve.
The British Formula 3 champion is testing with Toro Rosso in the Abu Dhabi young driver sessions this week as part of his development deal with Red Bull.
"The speed, the grip, the downforce, brakes it's all very different to F3," said Vergne. "Plus the team, working with so many people, they are all so professional – so my first day in Formula 1 has been a really good experience."
He felt the day had made a useful contribution to STR's 2011 build-up.
"Today we did some development of the car for next year and I'm pretty happy because I thought it would be hard to do this," said Vergne. "When we get programs in F3, we only usually do half of it, but I was quite surprised that we were able to do the whole program today."
Vergne said he had tried to stay calm and professional about his day.
"I wasn't really nervous, the preparation beforehand has been good and so all I had to do was jump in the car and drive," he said after going seventh quickest. "I did quite well today, so I'm happy, but sure everyone is quite nervous before their first day in Formula 1, I guess."