Nico Rosberg "not worried" about Mercedes performance

Nico Rosberg has insisted that he is "not worried" about the performance of his Mercedes ahead of the United States Grand Prix.

The German will start this evening's race in Austin from pole position, but appeared to be struggling to match teammate Lewis Hamilton's pace throughout previous practice sessions.

He told reporters: "We've had a few issues in general on the car this weekend, on both cars and so yeah, we need to try to get it all right for [the race].

"But personally I'm not worried about that at all because if I would start worrying about that, it's not going to be good for performance.

"So I'm very confident the team's going to get the job done and just concentrate on what I can influence on my driving. I'm not worried."

Rosberg sits second in the drivers championship, 17 points behind Hamilton.