Lewis Hamilton says Mercedes’ 2019 Formula 1 car “feels quite a bit different compared to last year” with the defending world champions focusing purely on familiarising itself with the new W10.

Mercedes collectively tallied up the second most laps of any team on the opening day of F1 pre-season testing, 150 laps between Hamilton (81) and teammate Valtteri Bottas (69), only behind Sebastian Vettel who produced 169 laps in the Ferrari.

Hamilton, who was on driving duties in the afternoon, says his feeling with the new F1 car is remarkably different to the title-winning W09 of last year but in a trouble-free day was content wit the progress produced.

“It’s good to be back in the car and it's great to see the car is running as smoothly at it is,” Hamilton said. “It feels quite a bit different compared to last year and we're now getting to know it, trying to understand the balance and trying to understand the characteristics we're working with.

“It’s been a positive first day, we got through our running plan and there's lots for us to learn about the new car which we will be working on.”

“We managed to squeeze quite a lot in to this first day of running, finding out both how the 2019 tyres are working and also learning about the way the car responds to set-up changes,” technical boss James Allison added, with Mercedes targeting better rear tyre performance from its W10 design.

“Today was not about absolute pace and we're reasonably pleased with the handling of the car and the way it is behaving.”

Bottas and Hamilton finished day one eighth and ninth place respectively on the final times, only ahead of the Renault pair, and two seconds off the best lap from timesheet-topper Vettel.