Ferrari: San Marino win no one-off

Some of Ferrari's rivals have expressed their doubts about Ferrari's chances despite their return to winning ways at the San Marino Grand Prix.

But Costa, the man in charge of the design of the 248 F1, is adamant in his belief that the Italian squad are back.

"We're definitely back to levels that I consider good and there's certainly room for improvements. Imola won't be a flash in the pan," Costa told Gazzetta dello Sport.

"We are taking the development forwards, so there will be new components in the next races. We want to improve step by step," said the Italian of the developments planned for the next race.

Costa also responded to comments from rivals Renault that McLaren's Kimi Raikkonen, and not Michael Schumacher, is Fernando Alonso's main rival in the title fight.

"Let him (Alonso) believe that, so we'll be able to work a bit out of the spotlights, and to do everything necessary without making mistakes or having problems," Costa added.

"With Schumacher at this level, obviously besides Renault there will be us fighting for the title and let's not forget McLaren."

Costa, who replaced Rory Byrne at the helm of Ferrari's design team, said that, despite last year's poor performance, he has never felt questioned.

"No, never. I've always felt full trust around me, and I couldn't work if it wasn't like that. This car isn't just 'mine', but it's the fruits of the collaboration and design to build what I had in mind.

"Last year was the first chance, and then you learn. I have a more aggressive approach on the technical aspect, and the entire group has a more determined approach.

"The big secret is to keep focussing on the details, to put them together and to extract the maximum from that. There was no revolution but soft evolutions."