Lewis Hamilton hailed an "amazing" first day of 2016 testing after the reigning Formula One world champion racked up 156 laps in Barcelona on Monday.
Ferrari's Sebastian Vettel clocked the fastest lap at the Circuit de Barcelona-Catalunya, but Hamilton recorded the second-quickest time in his new W07 Hybrid.
And the Brit, who won a third world title last year and second in succession, was delighted with the mechanical consistency he enjoyed a month before the season starts in Australia.
"It's been an amazing day," said Hamilton.
"I've never had a day one practice like today. To get in a new car and have no problems is just a remarkable job by the team. So, for me, it was encouraging.
"But I tell you, 150 laps is quite long here!"
He added: "It was encouraging and there was no need to find motivation. The motivation was to get the car as far as possible in terms of distance because that will put us in good stead for the season.
"However, the training has paid off, and to be able to do that today, I feel really happy."