Rosberg upbeat on Mercedes progress

The German driver moved to second place in the standings after finishing on the podium in the Chinese Grand Prix, and is hopeful the updates introduced from this weekend's race in Spain will help him stay in the championship fight.

"I'm very pleased with the position in the championship," Rosberg said on Thursday. "I really think we've made the best of the first few races to be where we are, with a car that was not possible to win with. But it's a really good base to build on now.

"We are second and if we really develop like we are hoping to... I was in the factory a couple of days ago and it was very promising what they showed me in terms of development. So I'm very optimistic that we can be very strong. If it's enough to stay in the championship battle we need to wait and see."

When asked when he expected to have a winning car, he said: "It's difficult to say because it depends on the others. We are doing a great job in the development, that's for sure. I think everybody at the team, led by Ross, has been pushing well and really making it happen.

"We'll get a very good idea this weekend of how we are able to develop compared to others thorough the season, and then we can make more realistic predictions about how far we'll get and if we are able to reach Red Bull or not."

Rosberg admitted he was also cautious about his team-mate Michael Schumacher's form despite a slow start to the season by the seven-time champion.

"We need to be careful with that, because it's early days. And I can say for sure that in Malaysia, which was the third race, we were even. He was very fast in Malaysia and Shanghai it was a completely anomaly so we need to wait and see.

"I'm still in the mind-frame that he's going to be strong here and that it's going to be a battle between us for the rest of the season. I'm convinced that I can on his level or near anyways and so it should be a strong season for both of us."