Petrov: Braking trouble caused spins

The Russian had a spin on each of his two days in the car, which he put down to struggles with the car's KERS unit.

But he is optimistic that he will be able to focus on general set-up work next week at Barcelona after making changes towards the end of Friday's running.

"We found some good things on the brakes, which is very important for me," said Petrov. "It is my first time using the KERS, so we spent a lot of time working on this area.

"It was very difficult to find the right set-up. With KERS it is very different to last year; when you first hit the brakes, the rear is locking straight away.

"We pushed and went the right way with this all day, and in the last minute we went out and I was checking the brakes. Now I hope it works for Barcelona."

Renault had planned to do a full race distance run this afternoon, but the team lost time due to what Petrov described as a "fluid leak". However, he was pleased with the amount of work carried out over his two days in the car.

"It was positive for us, we sorted out a lot of problems and understood a lot about the car," he added. "In Barcelona I think we can do some proper tests."