Mercedes is set to turn its focus to finding more performance from the W03 in the second Barcelona test next week after a solid start to running with the new car at Catalunya.
Having run its old car at Jerez, this week's four day test in Barcelona marked the first appearance of the new car – with the team having also completed a day of running in private before joining its rivals in action.
Declaring himself happy with the testing carried out so far with the new car, team boss Ross Brawn admitted that the focus would now turn to finding more performance from the car with the objectives set having still to be achieved.
"We have had a very positive first week of running with the F1 W03,” he said. “After five full test days, we have completed over 2000 km, Nico and Michael have done consistent mileage and reliability has been ok, aside from a couple of problems earlier in the week. Both drivers have already completed full race simulations, and this really is a tribute to all the hard work that was done back at base in Brackley and Brixworth to ensure we hit the ground running this year with the new car - as well as to the efforts of our day and night shifts at the track in Barcelona.
“This basis means that the drivers and engineers have been able to work well with the car rather than chasing problems, and next week we hope to focus even more on getting performance out of our current package. Overall, we are in a reasonable position, but I don't for a moment believe we have achieved our objectives yet.
“It may be something of a winter testing cliché, but there is still an awful lot to be done, and it's far too early to make any kind of judgement about our competitiveness."
Rosberg, who drove the car on the final day of running on Friday, also praised the progress made already as the team looks to improve on its fourth place last year.
"After our first full test with the F1 W03, I can see that we are making good steps forward,” he said. “Our test programme went well this week and we have made evident progress each day. In terms of reliability, the car is performing pretty much as we expected which is really important as we can concentrate on improving the performance.
“Of course it's difficult at this stage to predict how we will fare in race conditions against our competitors but overall I'm pleased with the start that we have made. I'm looking forward to the final test next week before the season begins, and continuing our learning with our F1 W03."