Rosberg under no illusions over progress

"I'm not worried, but it's going to be very difficult to move far up from where we are," said Rosberg, who is yet to score a point after the first two races.

"We are not extracting everything from the car and that's what we need to work on. We are still lacking pace compared to where we want to be, so it's a combination of both."

Mercedes started the season with high hopes - talking up its chances of fighting for race wins - but its pace has been far from that of the leading squads.

Rosberg admitted he has been shocked by the lack of competitiveness of his car.

"I'm very surprised at where we are because we are such a strong team led by Ross [Brawn]," he said. "It's surprising to be where we are at the moment and I don't have an explanation why."

The German said there is not specific target for the team now, other than to make progress towards the front.

"Well, Ferrari is quite a way behind them, so the aim is to progress. There is no specific aim.

"We need to get the updates working properly and the car working properly - the rear wing isn't working properly - so when we get everything to work, we will see where we are."