Jenson Button has claimed that McLaren's 2010 pairing will 'be tough to beat' and expects former team boss Ross Brawn to understand his reasons for quitting the Brackley team to join one of its biggest rivals.

Speaking to Reuters while promoting a new book reviewing his championship-winning 2009 campaign, Button revealed that he had spoken to Brawn on Wednesday morning in a bid to clear the air following the fall-out from his decision to join his predecessor as world champion, Lewis Hamilton, at McLaren for 2010.

"It's always disappointing to go your separate ways when you have been so close to someone who has really helped you to win a title," he said, "but I think he understood my reasons behind it and we will stay friends, I hope.


"When I jumped into the Brawn car in March and realised we had a monster, it was a special feeling for the whole team after what we'd been through. I'm not sure if that emotion will ever be there again."

Deflecting further accusations that he had chosen to switch sides in order to achieve the financial reward for his title success that he had been demanding at Brawn, Button again insisted that he was going to McLaren for the challenge of pitting himself against Hamilton as well as trying to pursue a second F1 crown. That test, he claimed, was something that had stirred him even before last week's much-publicised visit to Woking, where the finer points of a deal are believed to have been cemented.

"I had feelings that I wanted to be fighting there alongside Lewis before that meeting, and it wasn't that day at the factory that clinched it for me," Button maintained, "It was at another time and place. It was only a couple of weeks ago that I knew it was a possible option and it made me very excited. It definitely came from the heart, that decision to move to McLaren and to be fighting with Lewis Hamilton in the same car."

The word 'challenge' featured strongly in Button's interview, as he reiterated questions that he first raised after celebrating his title with a run to third place in the inaugural Abu Dhabi Grand Prix earlier this month.

"It was a very special feeling [to know] that I had achieved what I set out to achieve in F1, but I immediately thought 'where do I go from here?'," he continued, "I've been very comfortable within [Brawn] and [the McLaren move] is taking me outside of my comfort zone. But that's what excites me. It's going to be a challenge going to a team where Lewis has been for three years and where he's won the world championship, but that's why I am doing it.

"I want to challenge myself, I want to challenge Lewis and that is so exciting for me. That's the reason why I am going, I'm not going because it's going to be easy, I'm going because it's going to be tough, but it is a challenge I am definitely up for."