Button says he is still in the thick of the title race
Reigning world champion Jenson Button says he thinks the title race is still wide open, despite him lying fifth in the standings with four races left.
The next race is in Japan, where McLaren driver Button has never won a race, but he said he felt confident.
"Obviously there's no room for mistakes but any of the top five drivers could easily steal the title," he said.
"It might seem a disadvantage to be behind in the standings but make no mistake, I know I can win this title."
With four races left in the season, Button has 177 points, 25 fewer than championship leader, Red Bull driver Mark Webber - exactly the amount available for a win.
Ferrari's Fernando Alonso is second, with McLaren's Lewis Hamilton third and Red Bull's Sebastian Vettel fourth, four points ahead of Button.
The defending champion has only been on the podium in one of the last six races - three of which have been won by Alonso, two by Webber and one by Hamilton.
Last time out in Singapore, Button came home in fourth place, but he said he felt confident of making a serious challenge next time out at Suzuka.
"I love the whole Suzuka experience," said Button, whose girlfriend is half-Japanese.
"The whole atmosphere is invariably extremely tense and frantic because the race always plays such a decisive role in the outcome of world championships.
"I think it's a circuit that suits my style - it's all about scrubbing off as little speed as possible through the corners and maintaining a very smooth and precise rhythm: get it wrong and you're usually scrabbling to regain your momentum for several more corners. It's a punishing place."
Hamilton echoed Button's remarks about the demanding nature of the Suzuka circuit, where he finished a brilliant third in an uncompetitive car last year.
Hamilton has retired from the last two races after collisions with other drivers, but he said now was "not the time to hold back - it is the time to fight.
"You need to be committed and precise to do well there, and there's no room for error either: no Tarmac run-off, and all the barriers are pretty close, so any mistake is going to hurt your chances big-time.
"Suzuka is very much unfinished business for me. I raced the best I could last year, but our car just wasn't fast enough.
"This year, I'm holding nothing back - I need a strong result to get my title hopes back on track, and that will be my complete focus from the moment I first sit in the cockpit on Friday morning."