F1 World Championship leader Jenson Button is adamant that far from entering the final two grands prix of the 2009 campaign under pressure to hang onto his ailing advantage, it is in fact his title challengers Rubens Barrichello and Sebastian Vettel who should be feeling the heat.

Button will arrive at Interlagos next week for the Brazilian Grand Prix - on Brawn GP team-mate Rubens Barrichello's home turf - needing just third place to wrap up the laurels regardless of where either of his two rivals takes the chequered flag. However, since the Turkish Grand Prix in Istanbul all the way back in early June, the 29-year-old has succeeded in scoring six points or more only once, when he finished as runner-up to Barrichello in the Italian Grand Prix at Monza - and in the last eight outings he has got the better of the most experienced driver in the field on a mere three occasions.

That has enabled the S?o Paulista to close the gap at the top of the drivers' standings to just 14 points with 20 remaining to play for in Brazil and Abu Dhabi, and more significantly still, having appeared all-but down-and-out off the back of a run of chronic ill-fortune, poor pace and unreliability, Sebastian Vettel's imperious Japanese Grand Prix victory at Suzuka at the weekend has vaulted the young German right back into the reckoning too at 16 markers adrift.

What's more, Button is constantly being reminded of the unnerving statistic that two years ago his countryman Lewis Hamilton surrendered an even greater margin of 17 points in the last two races to lose out on the laurels to Ferrari's Kimi Raikkonen in a nail-biting Interlagos finale. Twelve months later, the McLaren-Mercedes star returned to S?o Paulo to deprive home hero Felipe Massa of glory quite literally at the last gasp - and twelve months later again, the throngs of partisan supporters expected to attend the race will be hoping Button does not make it England 2, Brazil 0 in his own internecine duel with Barrichello. Either way, the Frome-born ace insists it is not he who is facing the toughest task.

"For whatever reason, he (Hamilton) didn't score the points," Button is quoted as having said by the Daily Telegraph, "but I don't feel under pressure. The closer we get to the end of the season, the more pressure there is on the people chasing me. It's an interesting situation, but Rubens and I get on well so we'll see what happens when we get [to Interlagos]. I'm not worried; I like S?o Paulo and I still have a 14-point lead, let's not forget.

"It is about not making mistakes - that is the most important thing. I go to Brazil positive and looking forward to the challenge. Sebastian is quick and the Red Bull seems very quick. It (Interlagos) has still got high-speed corners and they have shown they are quick in low-speed corners like in Singapore, so they will be difficult to beat, and Rubens is always quick there. It is going to be a challenging weekend, but a fun weekend as well."

One title that looks rather more comfortably within reach, by contrast, is the constructors' crown for Brawn GP, with the former Honda F1 outfit requiring just half a point to seal the deal. Button argues that when - for surely it is now when, rather than if - the Brackley-based operation finishes the job off, it will be a supremely well-deserved success.

"It has been a rollercoaster throughout the season and also last winter," the seven-time grand prix-winner reasoned, "so if it does happen then congratulations to everyone. Also, after such a difficult winter, we didn't even think we would be on the grid in Australia, so to come away with a victory there and many [other] victories this season, and then to come away with the constructors' title will be a very special feeling."

Meanwhile, Vettel's boss, Red Bull Racing team principal Christian Horner - who prior to Monza had quipped that Button was 'like Stuart Pearce taking a penalty' - is confident that the chase is on, with the entire efforts of the energy drinks-backed concern able to be focussed upon the 22-year-old now that team-mate Mark Webber is mathematically out of contention. Should the man from Heppenheim finish any lower than second in S?o Paulo, however, his bolt will be shot.

"They thought they would be stronger in Singapore as well," Horner - a former racer himself - opined of Brawn's assertion that they will be in better form at Interlagos than Suzuka, where Barrichello and Button took the flag respectively a lowly seventh and eighth as Vettel effortlessly triumphed. "There's no reason why we can't be strong in Brazil, and having [only] one driver in the championship makes it easier. We can be totally behind him. We are focusing on winning the next two races - we can't do more than that. We will do everything to support Seb.

"There are three drivers with different approaches. There is Jenson, who has seen his lead eroded over the second half of the season; there's Rubens, and for him it looks like his big chance; and then there is Sebastian, who has nothing to lose. Psychologically, it will be fascinating."