Sergio Perez urges Sauber to keep developing promising C31

But he insisted that the Swiss team must keep working hard to develop the car right up to the first race in Melbourne to capitalise on it.

The Mexican, who impressed on his debut at Melbourne nearly a year ago by finishing seventh on the road, was second fastest overall after two days of testing at Barcelona and ended Wednesday just 0.040s slower than the best time - set by Force India's Nico Hulkenberg.

"I think we are optimistic of course," said Perez afterwards. "It's a good starting point for us, but we must develop our car from now to Melbourne - we have to find performance because most of the other teams will too.

"It is really important to push the maximum to try to get the performance before Melbourne which will make the difference now. I believe that we are now in a good position, but everything could change when we get to Melbourne."

Perez said the team plans to bring more developments to the final test at the end of next week and added that he believed there was more time to come from the car through set-up work.

The Ferrari Academy driver also revealed that he felt in a far better shape approaching his second season than he had in his rookie year.

"Physically I am a lot fitter than last year as a starting point, so I have done a very good training during the winter," he said. "Mentally with my engineers the communication is a lot better too, so I am very well prepared for this season and I am looking forward.

"[Circuit knowledge] will help a lot. It's not just knowing the circuits, but being used to the complete race weekends. I already have the information from last year now; what happened in that race weekend, how conditions are change, what we have to change - so I can guide the team a lot more than I could last year. In that side it's how experience counts."