Button delighted strategy paid off
Jenson Button insists he is not yet thinking about winning the championship despite swelling his lead to 14 points with victory in the Spanish Grand Prix.
The Brawn driver led team-mate Rubens Barrichello, his closest challenger, to a Brawn one-two to secure his fourth win in five races this season.
He told BBC Sport: "Every day I think, 'Wow, I'm leading the championship!'
"But I'm not looking to the last race at all - 14 points may sound a lot but one error and it can all change."
The race at the Circuit de Catalunya on Sunday was a private battle between the two Brawn drivers after their biggest threat, Red Bull's Sebastian Vettel, was passed by Ferrari's Felipe Massa off the start.
The German spent the entire race bottled up behind the Ferrari and ended up slipping to fourth behind team-mate Mark Webber, who outfoxed him on strategy, and is now 18 points adrift of Button with nearly a third of the season gone.
But Button said: "There's no way I'm looking to Abu Dhabi (the final race of the season) just yet - my only thoughts now are on the next race in Monaco.
Barrichello blames race tactics
"I have to stay relaxed and I have to stay focused. I'm leading now but it can all change so quickly.
"Rubens is obviously very fast and he is doing a great job, while the Red Bulls are right up there, too. It should all make for a good race in Monaco as we battle for places."
Barrichello, meanwhile, was left to rue another second-place finish, admitting his three-stop strategy worked against him.
"At the end of the day I can hold my head high because I have done my best and the set-up was good, it was just the strategy didn't work," said the Brazilian.
"I believe I have the ability to win races and the ability to win the championship, but everything is going Jenson's way at the moment.
Everyone (on the outside) is wondering what's going on, but the car is that bad. I am driving the socks off it but I've got no hope
"I'll be honest, I was surprised they changed Jenson's strategy. We were both on a three-stop so I don't know why they changed his and not mine. Still, with the pace I had, I thought I had the race in the bag."
Brawn took the decision to switch Button to a theoretically slower two-stop strategy at his first stop because they feared he would otherwise be caught in traffic.
But the 29-year-old was able to use his altered tactics to leapfrog Barrichello, who had taken the lead at the start, as the Brazilian struggled with his tyres after his second pit stop.
When asked if he feared Brawn were now favouring Button in his bid to win the title, Barrichello replied: "I hope not. I've been in a team that very much favoured someone else before.
"(Team boss) Ross Brawn has been in that position too (while at Ferrari) but he likes me very much I think."
Barrichello was referring to his six years as team-mate to Michael Schumacher at Ferrari, where Brawn was technical director.
Button was also keen to play down the significance of the split strategy, saying: "There was an advantage to be had with a three-stop - and I still think that.
"To be fair, I think Rubens had problems during his middle stint and it didn't work for him... (but) I was lapping 0.6 seconds faster than anyone, which must prove it wasn't just the strategy (that earned him the win).
"I went on to a two-stop to act as a buffer for Rubens, but it worked out a lot better than we expected."
Button lapped countryman Lewis Hamilton, the reigning champion, on his way to victory - and the McLaren driver cut a dejected figure after the race.
"What can I say, what can I do?" he said after finishing ninth. "I drove my heart out, as I always do, but that car is just not good. I just had no grip.
"At the moment, for sure, I don't have a car to win the championship. The team have done a fantastic job, we have great reliability and morale in the team is fantastic - it's just a shame that they haven't given me a car to defend the championship.
"Everyone (on the outside) is wondering what's going on, but the car is that bad. I am driving the socks off it but I've got no hope."