Vitaly Petrov believes he will need to adjust his driving style if he wants to get the best out of Caterham's car.
The Russian, who was only confirmed as a Caterham driver last week, had his first taste behind the wheel of the CT01 on day two of the second pre-season test in Barcelona.
After spending two seasons with Lotus Renault, the 27-year-old knows things will be slightly different at the Hingham-based squad.
"Physically I feel really good. It's obviously been a while since I've been in a car, but I've kept up my fitness levels and I enjoyed myself on track, so it's a good first day back," he said.
"One thing I have noticed is that this car behaves a little differently from my previous experience and I think I may have to adjust my driving style to get the best out of it - I've been quite aggressive before, but I think this car responds better to smoother inputs, so that's something I can work on, and work with the engineers on."
Petrov completed 69 laps at the Circuit de Catalunya on Wednesday, posting a best time of 1:26.605.
"I think that was a pretty positive day," he said.
"We completed 69 laps and got through most of what we had planned. This morning we had a couple of issues with the seating position and the brakes, but you expect that from a new car and they were little things that we were able to fix quickly.
"In the afternoon we put in a few more long runs and that'll give us a lot of data to work on tonight and I think tomorrow it will be more of the same."
Mike Gascoyne, chief technical officer added: "A very reasonable first day with Vitaly in the car. We spent some time this morning getting him acclimatised, focusing particularly on the brakes, but he has settled in well and did exactly what we asked of him today.
"We have a few points to work on tonight, one of those being to understand how to give him a setup he feels most comfortable with, so tomorrow we expect to be able to continue to progress when he's back on track for the second day."