Andre Lotterer declared himself happy with his first day as a Formula 1 driver, following his solid showing for Caterham through Friday's Belgian Grand Pix practice sessions.
The German made a impressive start to his Caterham career, outpacing his team-mate Marcus Ericsson by 0.091 seconds in the first session, before finishing just 0.043s in arrears of the Swede in the second session.
"I think it ran pretty smoothly," he said.
"I had to learn a lot in a short time and go step-by-step, to find the driving style of the car, the tyres and to handle the power.
"I'm still a bit behind on understanding the functions, but getting there. I tried a few launches, things like this.
"In terms of speed I'm just building it up. I think for sure there is more to come. But I think I'm quite pleased with everything.
"I'm trying to understand everything as much as possible. It doesn't look like I'm miles off, so for the first on the option tyres, it's OK. I feel that there is more to come, and we can improve the car. We're getting there."
Lotterer, who is a frontrunner in Japan's Super Formula series alongside his Audi LMP1 career, says he was surprised at how little grip F1 cars have, particularly on the prime tyre.
"In the first practice session I was obviously only on the prime, with not that much grip. I expected more speed through the corners," he added.
"The power is quite impressive in these cars. But also what's impressive in a more negative way is the grip.
"We don't have a whole lot of grip, so you have to be very patient to get on the throttle, and it takes a long time to really apply the power."
Caterham performance director John Iley said Lotterer was already proving F1 had missed a trick by spurning him in his youth.
"Possibly he should have been in Formula 1 10 years ago," said Iley.
"I think he subsequently proved in world sportscars and Japanese single-seaters that he would have been more than vindicated in being Formula 1.
"He's well known to the owners and the management of the team. They rely on good feedback and we're basically getting his experience and feedback on the car during this weekend and he's done a very solid job for us so far."