By Sarah Holt
BBC Sport in Barcelona
Button has driven superbly so far this season for debutant F1 team Brawn GP
Championship leader Jenson Button says he must take an "aggressive" approach to Sunday's Spanish Grand Prix if he is to maintain his title challenge.
The Brawn GP driver leads by 12 points but many of his rivals are expected to unleash upgraded cars in Barcelona.
"You have to be aggressive at this point in the season - you cannot settle for second or third," said Button.
"You have to be fighting for the win in every race otherwise you don't have a chance of winning anything at the end."
Three victories - in Australia, Malaysia and Bahrain - out of four races so far this season have propelled Button to the top of the championship ahead of his team-mate Rubens Barrichello.
The Englishman's advantage could have been even greater had he not been awarded half points in Kuala Lumpur when the race was cut short by heavy rain.
However, despite his early advantage Button - who finished sixth last year in Barcelona for Brawn's predecessor Honda - is not taking anything for granted.
We don't have enough of a lead yet to think about the championship
"We don't have enough of a lead yet to think about the championship," said the 29-year-old.
"It is a little bit frustrating when you've won three races to only have a 12-point lead but for now we need to concentrate on this weekend.
"I don't think any team would honestly be thinking about the championship after just four races."
Button and Brawn will be once again targeting the top step of the podium at the Circuit de Catalunya, but will keep a close eye on the chasing pack.
The first race of the European leg of the season sees many teams unveil a raft of aerodynamics updates.
Toyota, who lie third in the constructors' championship behind Brawn and Red Bull have a significant package of aerodynamic upgrades ready, including modified front and rear wings.
Defending champions Ferrari, who are languishing in ninth place, are expected to introduce a host of major aerodynamic updates after some positive development work in Italy.
Team principal Ross Brawn will also provide both Button and his team-mate Rubens Barrichello with a series of upgrades, including new sidepods and an updated version of the controversial double-decker diffuser.
But Button remained cautious about predicting just how advantageous his team's upgrades would be in comparison to their closest rivals.
"It is an important weekend," said Button, who believes the aero tweaks will help improve the balance of his Brawn - an issue he has complained about in the past.
"We've got a new package here and we won't be getting another upgrade immediately so this package should give us a good jump in lap-time.
"We have to hope what we have is enough to put ourselves in front of the Red Bulls because they are improving all the time.
"McLaren were very strong in Bahrain and weren't very far off us at all.
"I don't think we had the quickest car in Bahrain. We did well on strategy by getting in front of Sebastian Vettel and Lewis Hamilton early on.
"But if you saw our car before the start of the last race our car was looking a bit tired, to have everything perfect here will make a difference.
"We just have to take each race as it comes and be up there challenging for the win each time."
Button, and everyone else, will get a first glimpse of the tweaked cars of rival teams when first practice begins on Friday at 0900 BST.