Rosberg eyeing victory at United States Grand Prix

Nico Rosberg knows he has nothing to lose as he looks to close the gap on Mercedes team-mate Lewis Hamilton at this weekend's United States Grand Prix.

German Rosberg trails Hamilton by 73 points in the drivers' standings after he was forced to retire at the Russian GP a fortnight ago, which the latter won.

The Grand Prix in Austin on Sunday is one of only four rounds remaining in the Formula One season, meaning there are still 100 points still up for grabs.

While the gap between the two appears insurmountable, Rosberg admits he has not given up hope of a first world championship.

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

"I've never thought about finishing third because with my car I'm still on for first at the moment and that's what I'm thinking about.

"It's tough because I'm realistic also, and I need a lot of luck as well and all that. I'm fixed for that until you tell me it's not possible anymore."

Ferrari have emerged as Mercedes' biggest competitor so far this season, but Sebastian Vettel's chances in Austin took a hit after incurring a 10-place grid penalty for replacing his engine.

"It makes it more simple for us, the weekend," Rosberg said.

"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."