© Getty Images Enlarge

Sebastian Vettel says his new Ferrari is a "massive step" ahead of the Red Bull he was driving last year.

Vettel struggled with the Red Bull last year, which suffered from a power deficit to the pace-setting Mercedes but was still quick enough to secure second in the constructors' championship. Ferrari struggled to match Red Bull last year, but with a winter of development seems to have closed the gap. Although a 2015 car is expected to be better than a 2014 car, Vettel's comments suggest Ferrari has made a good step.

"I think it's a step forward," he said of the Ferrari. "I didn't drive last year's Ferrari but I think compared to the car I had last year it's a massive step. People generally seem happy, but it doesn't necessarily mean we are satisfied. If you want to win you need to beat Mercedes and that's the target."

Vettel completed 143 laps in the Ferrari on Friday, but despite the impressive reliability he has yet to set a time within two seconds of the fastest lap of the reigning champions Mercedes. Vettel said there was a lot of work left to do during his final day in the car on Sunday, but made clear he had not yet attempted a quick lap on low fuel and soft tyres.

"I think there is a lot we can do better, but I think at the last day [of testing] we would like to use it to get in the zone for Australia," he said. "It's an important day for us and if I had to pinpoint one thing it would be to be a little bit quicker, but it's difficult to say how quick we are right now because some people tried a little bit more towards quali trim and some people less. I think being quicker is never bad and always helps."

Despite some promising pace early in testing, Vettel said there was no guarantee that Ferrari would be second best to Mercedes in Melbourne.

"It would be nice to find out in two weeks we are right behind them, but I think it will be very close [among the others]. I don't think it is any secret that Mercedes should be the quickest and anything else would be a massive surprise - I don't think you can give away that much advantage in a couple of months. Then it's exciting to see what is going on behind, but from the laptimes we see it is not clear."

© ESPN Sports Media Ltd.