Nico Rosberg believes this year's Mercedes W03 represents a big a step made by the team.

13542 - 'We've made big steps as a team' - Rosberg

The team launched the car at the start of the week after performing some private testing and has completed 399 laps of the Circuit de Catalunya between Tuesday to Friday.

Asked if he was happy with the car, Rosberg said: "We want to win so we are definitely not there yet. But we are making progress and that's really good to see. The team is going in the right direction and also just in terms of the car build, the work that they've done at the factory is so much better than in previous years. Everything fits together well, it's very clean and it's performing as expected. From there we can see that we've made big steps as a team."

Rosberg has yet to win a race in his career and Mercedes boss Ross Brawn admitted the new car would not be in a position to pick up victories at the start of this season, but Rosberg insists he is not frustrated.

"It's not frustrating because it's a great motivation to be a part of this push that is happening at the moment in the team," he added. "The progress is evident, which is really nice to see, and everybody is motivated as a result. As soon as you see progress then you get that extra motivation because you see that things are happening and now we can move forward and get there."