Sebastian Vettel says it wasn't the ideal day for him but is confident his team can rescue it in time for the race as he hunts a first win of the season.

The Ferrari driver topped the opening session at the Circuit de Catalunya with a 1m 23.951s - a lap which put him comfortably underneath Nico Rosberg's pole position time from last year - but in the afternoon session he failed to replicate the pace to slip to fourth with a best lap of 1m 25.017s.

Despite the promising FP1 Vettel says he found it difficult to nail the balance of his Ferrari on longer stints in the second session which is something he wants to rectify overnight ahead of the final practice on Saturday morning.

"This afternoon was a bit trickier for us not as good as the morning," Vettel said. "We can still work on the car and improve overnight we are usually quite good at that even if today was not the perfect day we should be better tomorrow.

"Yes, even with the red flag we did but we are not as satisfied as we could have been. It was a bit tricky getting the car in the right window but usually we are quite good at getting it right on Friday night for Saturday so I'm looking forward to that.

"In the end it is Friday so we need to be careful with our judgments. The first impression of the pace was good whether we can confirm it tomorrow depends on what other people are doing today but we can make a step so we should have a stronger Ferrari tomorrow."

With Ferrari chief Sergio Marchionne looking for the Italian manufacturer to claim a first win of the season sooner rather than later and pointing to the Spanish Grand Prix as a strong possibility, Vettel says the team has plenty more to give but can't be too confident until it discovers the true pace of the dominant Mercedes.

"It is never too soon to start winning, we all know where we want to go," Vettel added. "We want to win that is why we are here not to be second, but equally we know our opposition at this stage is very strong. We have a couple of things coming this weekend that should make it more of a challenge for them."