After a difficult start to the week, Mercedes fortunes improved dramatically for the final two days of testing at Jerez, drivers Nico Rosberg and Lewis Hamilton completing 293 laps (over 800 miles) between them.

As the 'experts' murmured 'told you so' in the British driver's direction, Hamilton remained focussed and on Friday finally got some serious mileage on the W04. The smiling youngster leaving the paddock on Friday barely recognisable from the worried expression he wore on Wednesday.

After just two days in the car, Ross Brawn is clearly struck by Hamilton's focus and professionalism, qualities the German team desperately needs as it attempts to move forwards and take on the Red Bulls, Ferraris and McLarens.

"We have made it very clear to Lewis that he is part of the solution," said Brawn. "You have a choice in a team, are you the problem or are you the solution? He is part of the solution to get us where we want to be. He knows that and he understands that and I think he is relishing that.

"He gives his reference points and helps us understand what we have to focus on," he continued. "Some of it we knew already and that is why we restructured the aero group. I welcome that approach. It needs to positive and constructive but criticism of the right sort is helpful to a team, it drives you forward.

"He is very straightforward," added the Briton, who worked with Michael Schumacher throughout his glory years. "In many ways he is very simple and straightforward. He tells us what he thinks and he is never short of detail in telling you what he thinks and, of course, you learn what level of detail you need to go to.

"He is interested in everything about the car. He is interested in the fact the stickers might not be put properly on the bodywork. He has got a very good eye for detail. I think he is going to be a very involved member of the team, which is what we wanted.

"He is clearly a very talented driver but Formula One is about so much more," he admitted. "There are a lot of highly talented drivers who don't have the rest of it, but I think he has got the rest of it as well."

Reflecting on the nightmare start to the week, which saw Rosberg suffer a fire and Hamilton crash out after just 15 laps, Brawn smiled and admitted: "The first couple of days were difficult with the problems we had. But since then it has been as good as I could have hoped. Today was Lewis's first proper day. It took a few runs to settle in but once we got past that it has been very constructive."