Sebastian Vettel is sure Ferrari's SF16-H is a step forward from its predecessor after topping the first day of testing in Barcelona.
Vettel outpaced reigning world champion Lewis Hamilton by 0.470s at the Circuit de Catalunya, completing 69 laps in the process. The German has downplayed the significance of the lap time difference but admits he immediately felt comfortable in Ferrari's latest car.
"I think it is a step forward," he said. "It was the first proper day and it was good to get some laps and a first feel for the car, the first impression was very positive. I had good confidence straight away and felt at home, so that is a good sign.
"We know there is a lot of work ahead of us. Coming back on the result today, it is nice but it doesn't mean much. There is plenty for us to get on top of."
Vettel is refusing to get carried away after one positive test session in front of Mercedes.
"It is better to be first in about a month's time . It is better than being last but it is not really important. We are fairly happy with the car and the way it felt, we did some laps, ideally we wanted to do some more but when everything is new and you have issues to look into, you take a bit more caution, you stop and unfortunately these things take time."
Lewis Hamilton and Mercedes completed 157 laps in the first day, nearly twice as much as the nearest car.
Reflecting on the world champions' day, Vettel said: "It looks like they had a decent day. We do that many laps but we have plenty of reason to be happy, and we have plenty of things that we need to improve. Time is limited and in four weeks we will be in Australia. We know we have a lot of work to do."