Jenson Button may have recently toasted his dynamic start to the Formula One season, but he knows the fight has only just begun if he is to be crowned world champion.

Three wins from the opening four grands prix have catapulted Button into a 12-point lead over Brawn GP team-mate Rubens Barrichello and made him hot favourite for the title.

"We know we have a real fight on our hands from here to maintain our lead in the championship, but I am confident we are well prepared for the challenges ahead," said the 29-year-old from Frome, Somerset.

Button also has history on his side because in the 60 years of the championship, a driver has won at least three of the first four races on 17 occasions.

Only in three of those years - Emerson Fittipaldi in 1973, Alain Prost in 1988 and Ayrton Senna in 1989 - has that driver not gone on to take the title.

Fellow Britons Jim Clark (1963 and '65), Sir Jackie Stewart (1969), Nigel Mansell (1992) and Damon Hill (1994) all managed such a feat, so the pressure is on for Button.

The 29-year-old is totally aware of that as every team heads into Sunday's Spanish Grand Prix with a number of new upgrades on their cars in a bid to reel in the Brawns.

It was in Barcelona in March, just a couple of weeks prior to the start of the season, Brawn GP first served notice of what was to come with their debut outing at the final test session. On a familiar track, and in a car Button feels at home in, he has the opportunity to ram home his advantage on Sunday.

"Although the team only completed four days of testing at the Circuit de Catalunya in March this year, I know the track inside out," added Button.

"It feels very familiar to be heading back there for the start of the European season this weekend."