AUSTIN (AFP) - Nico Rosberg is aiming to take full advantage of Ferrari's grid penalties by winning this weekend's United States Grand Prix without giving any thought to his, or Mercedes team-mate Lewis Hamilton's, championship prospects.

He says his attitude is concentrated, but carefree and that he feels he has 'nothing to lose'.

The 30-year-old German can keep his own title challenge alive by winning Sunday's race or simply finishing ahead of defending two-time champion Briton Hamilton.

But he knows Hamilton will become a triple champion if he can outscore him by three points and four-time champion German Sebastian Vettel of Ferrari, who is currently second, by nine.

"My frame of mind is that I have nothing to lose," said Rosberg. "I want to win and I have the opportunity to win. It's a great target to have this weekend. I'm focused. That's it."

He added that the 10-place grid penalties that Ferrari will incur for their engine changes should make it much easier for him to achieve his objective.

He said: "It makes it more simple for us, over the weekend, but they're still a threat from where they are, because you never know with the weather or whatever. We'll see, but it could make it an easier weekend.

"As to the championship, you know I never thought about finishing third because, with my car, for sure I'm still on for first at the moment and then that's what I'm thinking about.

"Even if I know that it's tough, because I am realistic also, I need a lot of luck as well and all that, but I'm fixed on that until you tell me it's not possible any more."