Rosberg thrilled to unlock car's pace

Despite showing good form right at the end of winter testing, Mercedes has languished in the lower part of the top 10 at best so far this season.

But at Shanghai today Rosberg got up to the second row, within a few tenths of the McLarens.

"It's a positive day for us," said Rosberg. "It's been very difficult the last couple of weeks, but today we've improved the car, that's clear, and just with very simple, basic things - and a lot of hard work - and that's nice to see.

"We're not where we want to be but we're close to McLaren and we're way ahead of Ferrari, today at least, so that's a good thing. Even on race pace tomorrow there's a good chance I can do a good race because we've improved our race pace too."

He is optimistic that he can challenge the McLarens in the grand prix.

"I think we can put some pressure on them. It's going to be difficult, but we will see," said Rosberg.

"When you start fourth, a podium is never out of the question. It's a bit optimistic, but why not?"