Brawn: Hamilton will fit in

Mercedes team principal Ross Brawn has no doubt when Lewis Hamilton joins his team next season he will be fully committed.

McLaren counterpart Martin Whitmarsh last week suggested Hamilton had started to regret his switch to Mercedes after signing a 45million, three-year contract.

Whitmarsh further expressed hope the 27-year-old was thinking he had made "an awful mistake" that would spill over into next season given Mercedes have only won one race in the last three years.

Hamilton conceded on Thursday that Whitmarsh's remarks had surprised him, naturally insisting he had absolutely no regrets and he was "very, very happy with his decision".

For Brawn, Hamilton is "a key ingredient" in the team's bid to make their way to the front of the grid, to consistently winning races, and ultimately to potentially winning championships.

And Brawn is convinced that Hamilton is motivated enough to make his ambitions become reality.

"As an engineer you want to know your driver is the most competitive he can be, and Lewis is undoubtedly one of the fastest drivers in Formula One," said Brawn, speaking ahead of Sunday's United States Grand Prix.

"So none of our engineers can have any doubt we have the fastest driver we could get, which is one box ticked we don't have to worry about.

"Lewis is at the perfect stage of his career where, after being at McLaren a long time, this is the next challenge for him.

"He is hugely motivated to face this challenge. We've a driver who is massively motivated to help us succeed more in the future, so that's another great asset.

"There will be some ups and downs, some difficult days and some great days - he knows that and we know that.

"So Lewis is a very important ingredient in helping us get to where we want to be.

"I don't want to underestimate Nico (Rosberg) either, he is a very important driver in the process.

"But obviously adding a fresh ingredient like Lewis brings another perspective as well."

It could be argued with Hamilton on board, he will strengthen Brawn's hand when it comes to asking for funds to develop the car.

Brawn, however, believe the Mercedes board have already proven they are not afraid to splash the cash by signing Hamilton in the first place.

"I don't know that Lewis gives me clout, but it shows a commitment, that our company are committed to succeeding," added Brawn.

"To both persuade, and find the funds necessary, to bring in a driver like Lewis shows fantastic commitment."