Brawn says driving a slower car will be Vettel's biggest challenge in F1

That is the view of Mercedes GP team principal Ross Brawn, who believes that the true extent of Vettel's position among the greats will be made evident when does not enjoy a machinery advantage.

"For Sebastian, what will come now, which will be an interesting phase of his career, will be when he has not got the best car," explained Brawn, who famously helped Michael Schumacher turn around Ferrari after he joined the team following back-to-back titles for Benetton.

"I think you have a fantastic driver in the best car, and that combination is unbeatable. It will be interesting to see Sebastian's role, Sebastian's influence, Sebastian's position when perhaps he does not have the best car, he has to make it the best car, and has to create the best car.

"That will be another chapter of Sebastian Vettel when it comes - and it will come.

"Perhaps he will make it happen himself, because he will go to another team as he wants them to be successful, and the challenge for Sebastian will be exactly the same as it was for Michael, that you have won two world championships, so what is next? What is the new challenge for me? What is the motivation?

"For Michael the motivation was to go to Ferrari and make that successful. I am sure Sebastian will look at that because everybody thinks Sebastian is doing a great job, but the Red Bull is a fantastic car. His ambition may take him a different direction, who knows?"

Brawns believes that one of the attributes Vettel has brought to F1 is in being able to achieve great success without losing his bubbly personality.

"I think what happens with new guys like Sebastian is that he is a young, fresh guy - these drivers always have different characters. He brings a very natural relaxed approach, at least from our side, to his achievements.

"He is very easy externally, obviously quite different when he gets in a car which you can understand, but from a personality point of view he is very relaxed.

"Michael was always very intense, very concentrated on it. I am not saying Sebastian isn't, but the way Michael needed to approach the job to succeed was with a high level of intensity both within and outside the car, certainly at the race track.

"Take Michael away from the race track and he was great fun. But Seb seems a little bit with a lighter character. He is clearly a huge talent. And still seems to be getting stronger.

"This year everybody said wait until he comes under pressure and then you will see he won't cope, but he copes very well. And I think with another championship under his belt, then he will have another level of confidence that he will deal with. "