Mercedes' Nyck de Vries hailed his debut F1 run as "special", the Formula E charger feeling quickly comfortable onboard his team's championship winning W11 which he called "a car from another planet".
De Vries concluded his first F1 test second fastest, 0.262s behind pace-setter Fernando Alonso but over two tenths ahead of teammate Stoffel Vandoorne.
The pair indulged in short and long runs over the course of the day as they improved their knowledge of set-up changes, car balance and of Pirelli's tyres.
"Today was very special, making my Formula One debut," said de Vries. "What an incredible car, it's from a different planet really.
"You can brake so late and carry so much speed through the corners. It was a real pleasure to drive.
"I'm really pleased with the progression I made throughout the day and the work we completed. I was quite surprised with how quickly I felt comfortable in the car and the team was very supportive, doing everything they could to make me feel as comfortable as possible.
"A massive thanks to Mercedes for this very unique and special opportunity because it was a great day in the car."
— Mercedes-AMG PETRONAS F1 Team (@MercedesAMGF1) December 15, 2020
Vandoorne completed 82 laps of Yas Marina on Tuesday, or 28 less than his teammate. However, a PR commitment forced the Belgian to cut his afternoon short, but he nevertheless enjoyed a "smooth" day of running.
"I had a lot of fun out there today in the W11," said the former McLaren driver. "I managed to complete plenty of laps with both some short and longer runs.
"It was a pretty smooth day and I was quickest in the morning session as well.
"I want to say a massive thank you to the team for giving me this opportunity, because the chance to drive a Championship-winning F1 car doesn't come around very often and is very unique.
"It was a real privilege to drive W11 and a really great day. I had to cut the afternoon a little short because I had to leave to the airport for a PR commitment, but nonetheless I'm really happy with the day we've had in the car and the opportunity to end the year driving W11."