Jenson Button has revealed that he had to produce one of the most 'flat-out' and 'ragged' performances of his career to take his fourth Formula 1 victory in five starts in the Spanish Grand Prix this weekend - before insisting that a 14-point advantage in the title chase early on is by no means enough to be confident.

Having stormed to an unexpected and last-gasp pole position in Barcelona on Saturday, the British star found himself beaten away from the start-line when the lights went out by Brawn GP team-mate Rubens Barrichello, who seemed to have the legs of the world championship leader throughout the opening stint. The entire complexion of the race changed, however, when the pair pitted for the first time and Button was converted from a three-stop strategy to a two-stopper whilst Barrichello was not.

That - allied to the Brazilian's inexplicably poor pace on the 'option' tyres during his third stint - placed the ball firmly in Button's court, and as Barrichello was unable to open up enough of a gap, the Frome-born ace found himself comfortably in the lead once all the pit visits had shaken out.

The 29-year-old would go on to cruise to the chequered flag some 13 seconds to the good, having lapped significantly quicker than any of the other front-runners on the lesser-favoured 'prime rubber in the closing stages. It was not, though, he urged, quite as straightforward as it may have appeared from the outside.

"Having someone overtake you at the start is always a bad thing when you're starting on pole," he joked, "but when it's your team-mate and he's on the same strategy it was like 'oh no, you're kidding me!' I had a good start from pole, but Rubens had an absolute flier and I couldn't hold him off. I was sat behind him for the first stint and I kept radioing in saying 'Rubens, please push' because I wasn't building a big enough gap behind to [Felipe] Massa, and I thought I'd pit and then come out behind him when he pitted.

"I did get a big enough gap, though, and with the prospect of being caught behind [Nico] Rosberg they switched me to a two-stop, because I think they wanted to use me as a bit of a buffer to the Ferrari and also [Sebastian] Vettel so that Rubens would have clear air. That was the case, and obviously the two-stop worked better than we'd thought it would. The three-stop strategy was the direction that we had initially taken on both cars in Q3, and I still think it was an advantage; I just think that Rubens had a problem on his second set of tyres.

"On a two-stop strategy the car did feel very, very heavy in the second stint, but after a few laps the team came on the radio and said 'you can't do these lap times - you've got to push'. I pushed very, very hard in my final two stints to make the strategy work for me; that damaged the tyres quite a bit, but it was the time when it mattered, when Rubens was on his second stint on low fuel.

"I had to try and keep the gap as small as possible and I did that, but it was a pretty tough race because every lap was flat-out. You can maybe say that should be the way in every race, but it's not always the situation. This was a tough race; I had to drive the car a little bit different to how I normally would - I was very ragged, but it was the quickest way round here today. For me, the best time was on the 'prime' tyre at the end; I could consistently do lap times six tenths quicker than anyone, and that showed me it wasn't just the strategy.

"To come away with the win is a little unexpected, but it means so much to continue our run of success. Obviously Rubens is disappointed not to have got the win today, and he has been a huge help over the weekend in helping me overcome the issues that I faced on Friday. His turn will certainly come. There's a great feeling within our team and I am very proud of them for producing such a great car. A special thanks to all the guys back at the factory in Brackley and to Norbert Haug and Mercedes-Benz High Performance Engines. They supported our team through the difficult times, and we couldn't have achieved this without them."

Though he has now dominated four of the opening five grands prix of the 2009 campaign, still Button is refusing to countenance the thought of following in compatriot Lewis Hamilton's footsteps as the next British F1 World Champion. It is a good feeling to be on top after suffering so long in the doldrums, he acknowledged, but that is no reason to get carried away by it all.

"I wake up every half an hour and open my eyes and think 'wow, I'm leading the world championship'," he admitted. "That bit is definitely there, but am I thinking about the last race in Abu Dhabi? No, I'm not; that's not me at the moment. I'm looking forward to Monaco and I've got a 14-point lead, which sounds a lot but it's not if I have just one issue.

"I've got to keep my head; I've got to stay relaxed mentally but also be aggressive when it comes to strategy and the races. You can't take it easy when you're only 14 points in the lead. Rubens is obviously very quick at the moment - he's doing a great job - and the Red Bulls are going to be on us in Monaco. You're going to see an exciting race there, I think. It is very stressful, but I suppose in a good way."

"A fantastic result for the team today after a great deal of hard work to maximise the performance of our new developments this weekend," summarised the Brackley-based outfit's delighted team principal Ross Brawn, as the ex-Honda F1 operation now holds a commanding 29.5-point lead in the constructors' standings less than a third of the way into the season. "As we approached the window for the first pit-stops, it became apparent that Jenson would come out directly behind Nico Rosberg if we went with his planned three-stop strategy. We therefore made the decision to switch Jenson onto a two-stop strategy to ensure that he could run in clean air.

"I think [Red Bull] got held back again, which maybe was a bit fortunate for us because Vettel got controlled by Massa for the first part of the race, and I was very surprised to see them both come in on the same lap for their second stops - that's when we expected Vettel to have some free track time and come back at us. I think the performance of both cars was very similar today, but we had the breaks and we got the points. Our second one-two finish is a fantastic way to start the European season, and I am extremely proud of Jenson, Rubens and the team. Our thanks as always to Mercedes-Benz and all of our team partners for their continued support."