Sebastian Vettel believes the new Ferrari is an improvement from last year's car, having topped the times on the opening day of F1 testing at Barcelona.
The four-time champion put the new SF16-H on top of the times after 69 laps, outpacing world champion Lewis Hamilton in the Mercedes by over four tenths of a second.
Vettel said he felt at home with the car straight away.
"I think it's a step forward," Vettel said of the new Ferrari at the end of the day.
"I think the first impression is very positive. Generally it feels like a step up.
"I had good confidence straight away and I felt at home so that's usually a good sign. But we know as well there's a lot of work ahead of us still. Today's result is nice but it doesn't mean much.
"There's is plenty of stuff we need to get on top of, which is normal for a new car."
The German refused to get carried away, however, admitting it is still very early days.
"[Being first] is better than being last, but not really important. As I said, we are fairly happy with the car, the way it felt, so that was good.
"We did some laps. Ideally I would have liked to do some more, but naturally when everything is new and when you have... I wouldn't say 'problems', but some issues that you look into, then you take a bit more caution and you stop, you look and it takes time.
"We didn't do as many laps but I think overall we have plenty of reasons to be happy. Equally we have plenty of things we need to improve.
"Times is limited. It's no secret than in four weeks we'll be in Australia, so we know we have a lot of work to do."