Rosberg says practice vital in Valencia

The German, whose Williams team has struggled in recent races, is hoping that the Spanish city's circuit my throw up opportunities to shake-up the form book and level the playing field between the teams.

"On a street circuit, the problem is that there's no grip in the beginning," said Rosberg. "On a normal track you learn it in ten laps, but it will take more than that, maybe 20, to get the hang of Valencia.

"We'll really be taking a guess on the set-up from what we know of other street tracks, and then take it step by step through the weekend. So it's very important to keep the car on the track because if you crash, you lose a lot of time that the others will spend working on it.

"All the teams are starting at zero so it will be a big challenge for everyone to get the best out of it as quickly as possible in the limited time we have."

Renault's Fernando Alonso told SpeedTV: "It's not like a normal street track, it seems wide, like an American type of street circuit. But you will completely change your opinion and feelings when you run with an F1 car.

"We will need to maximise the Friday practice when we arrive there because it will be the only time to improve."