Rosberg hails Williams progress in 2009

"I'm pleased. The team is progressing really well, and we are right up performance-wise. It's nice," said Rosberg.

"Obviously McLaren has made a big jump and they are level with us now, I think. I think we are in a great position, because at the moment we are fighting to be the second best team.

"We are right up there. Red Bull is currently quickest, but then there's already us and McLaren. We are looking good at the moment."

Williams is currently in sixth place in the constructors' standings, but has been closing in on fourth-placed Toyota in the last few races thanks to Rosberg's performances.

Rosberg reckons part of his team's progress has come thanks to a better understanding of the car, but he admits bringing new parts at every race is helping make a difference compared to previous years.

"I think a lot of if is from understanding [the car], but also development is a factor," he said. "We are doing a good job. I'm pushing hard on my direction, which seems to be working well. So I think it's a combination of everything.

"It's nice to see because we've always struggled in development over the last few years and this year we are really stepping up the game and we are bringing new parts every single time and they are always working for us, so it's good."