Kobayashi cautious over early form

The Japanese 23-year-old set a 1m12.056s time, just over 0.3s slower than Ferrari's pace-setting Felipe Massa, having completed 96 laps in the new car. His performance backed up that of team-mate Pedro de la Rosa who also set the second fastest time on the first day's running in Spain.

But though the team has shown early promise, Kobayashi cautioned against reading too much into the lap times.

"It has been a really great start for us and we had no problems with the car," he said. "It was the first day for me and there was a really good feeling with the car.

"It's difficult to say where we are, the result was a quite good lap time, but with new rules and another team like Red Bull still to come it's difficult to say where we are. But it was a really good start."

Kobayashi added that he believed the new C25 to be fundamentally sound and that it was now a question of building up a data bank of information on the car, and admitted that there was more to come from himself as he grows with experience.

"I don't think that there are problems," he said. "It is important that the car is good, but we have to work hard in the test to improve the car. We have to take this opportunity and focus on improving for the next test.

"I still have to improve and there are many things I can do to get consistent lap times. I know I can do it because last year in Abu Dhabi my lap times were really consistent but I just need to get confidence in the car."