Jenson Button insists he still has a chance of retaining his F1 title despite losing further ground in the championship race in Singapore.

Button finished fourth in the F1 night race but was behind Fernando Alonso and Red Bull pair Mark Webber and Sebastian Vettel - who all sit ahead of him in the standings.

It means Button is 25 points off the championship lead going into the final four races of the year and with that being equal to a single race win, the former Brawn GP driver said he felt his hopes are still very much alive.

"Fernando's had two good races, and is right in the thick of things, but Lewis has retired from the last two races, and he's still right there, and both Sebastian and me are ready to strike," Button said. "I think the new points systems has definitely amplified what people think of the standings, but I've always imagined the points as they would have been under last year's system: so, in old money, I'm ten points off Mark, and Lewis is about eight or nine behind him. And, with four races to go, that's not much at all.

"When you say you're 25 points off the lead, that sounds a lot - but it's just easier for me to reference it by the old system. It makes it seem easier to understand and compute, too.

"For the second year running, I'm right in the hunt for the world championship. I'm already the world champion and I've still got every chance of holding on to my title. That's what I'm in Formula 1 to do, and that's why I signed for Vodafone McLaren Mercedes; to have that opportunity."