Rosberg stays cautious on Williams form

The new FW30 has emerged as one of the leading contenders to be 'best-of-the-rest' behind Ferrari and McLaren, thanks in part to BMW Sauber's difficulties, but the team have consistently played down their chances for the new season.

And although Rosberg and teammate Kazuki Nakajima have enjoyed another strong week of testing at Barcelona this week, the mood in the team has not changed.

In fact, Rosberg thinks that the team have got a major fight on their hands in that fight for places behind the two leading contenders.

When asked if he saw Williams as the third best team, Rosberg said: "That would be a bit too optimistic I think. I see us fighting with Renault and Red Bull. BMW are the only one I don't really know about.

"For sure it's going to be tight with Renault and Red Bull and I hope that from one track to another specifically we can get a bit of an edge over them. So our target is probably fourth in the constructors' championship at the moment."

Rosberg believes that rivals Renault will have received a big lift from the return of former world champion Fernando Alonso.

"His arrival just boosts every single person working there to do extra hours and extra work," he explained. "That's going to be a help to the team, but then I have to say that the drivers who were driving there last year weren't idiots and he is not going to revolutionise the team to win the world championship. There is no way.

"But I am sure he will bring the team forward a bit. How much I don't know."

Although Rosberg is not expecting sensational results from Williams this year, he says he has no regrets about committing his future to them - and is genuinely excited about their prospects for the new-look F1 in 2009.

"I am very happy where I am that's for sure, but of course there is a small part of me that wants to be in a race-winning car," said the German, who was one of the contenders for a move to McLaren as replacement for Alonso.

"But I will just have to wait a few more years. That's what I want to do, I want to win races.

"It's difficult, you come into F1 and you have won everything coming through. I always had the chance to win in every single race I have ever done before F1, and now it is just not there. It is strange. So there is that small part of me that wants a race-winning car under me."

When asked if he felt winning with Williams was possible, he said: "I hope so. That would be the dream to make it with Williams. We need to make a step this year and then another big step next year.

"We will have our chance next year. There is such a big rule change that everybody has a chance. It's going to completely mix it up again. That's the big chance that we need to take as team Williams."