Button: Pressure will test Webber

Although Webber holds the current advantage with an 11-points lead in the title standings over Fernando Alonso, Button believes the Australian will not find it easy coping with the extra strain of being the man everyone wants to hunt down.

Button knows only too well about the stresses of defending a title lead - having admitted that it got to him during the closing stages of last year's successful campaign.

"There are a lot of very talented drivers in F1 and when you feel you are under pressure you can make mistakes, so it could possibly make a difference," said Button at Suzuka.

"We all say that Lewis [Hamilton], Fernando [Alonso] and myself, we have all won a championship, so maybe that is less pressure - I don't really know. But I feel a lot more relaxed this year than I did last year.

"Mark has found himself in a position where he is leading the world championship and has worked very hard for that, but it is a very stressful position to be in. And no disrespect to Mark, he is a very talented driver, but it is a position he has never found himself in before.

"We will see how he copes over the next few races. He has a very quick team-mate as well, and is trying to claw points back on him. So there will be a lot of action over the next few races. It is about keeping your car clean with no tyre marks on it, but also pushing it to the limit and getting the most points you can. It is a tricky compromise but that is what makes it fun."

Although Webber's Red Bull Racing team is favourite for victory in Japan this weekend, Button is confident that McLaren will be in better shape than it was in Singapore a fortnight ago.

"We come here knowing that the Red Bulls are quick on this type of circuit, and Ferrari has improved a lot on low speed and high speed circuits," he said. "In the last two races they have been very strong, but we come here with some upgrades and upgrades that should work very well around here.

"I've driven the car in the simulator as we do after every race and, forgetting the upgrades, I personally feel that I have improved the car from Singapore. I felt we were lacking in some areas and have changed the set-up quite a bit to help that. Putting upgrades on the car we've made a step forward as well.

"I don't know if Ferrari or RBR have big upgrades, but we definitely have an upgrade that will make a difference - you will definitely notice a difference."