Button is 18 points behind Schumacher

Schumacher won the first five races of the season, leading many to predict he would waltz to a seventh world title.

But he crashed out of last weekend's Monaco Grand Prix, while BAR driver Button went on to finish second.

The Briton said: "It's not over yet - we are still only a third of the way though the season. If he has a weekend like last weekend it could happen."

Schumacher is 12 points ahead of his Ferrari team-mate Rubens Barrichello going into Sunday's Grand Prix at the Nurburgring.

Button is a further six points back in third.

Button said: "Rubens, if he gets in the right groove, can still do quite well. If Michael has a problem or something there's a chance. "

Button came within half a second of his maiden grand prix win at Monaco after finishing marginally behind Jarno Trulli in a thrilling late charge.

If I win the championship I don't mind if I haven't won a race Jenson Button

"It was a great weekend really and that was the maximum we could do," Button said.

"I think I pushed really hard - I couldn't have pushed any harder, the car was on the limit all the time."

And Button insisted he was not worried at having finished second three times this season, but never won.

"It proves we want to go out and win. It's great to win but if you win one race and don't finish three, it isn't worth it because you get eight points for second.

"That might be a mistake in the points system because you might settle for second place.

"If I win the championship I don't mind if I haven't won a race. I'll be the first racing driver to never win a race and win the championship."

All the drivers will get together to air their grievances before Sunday's race.

Button complained about being held up in Monaco by slower cars, particularly the Toyota of Brazilian Cristiano da Matta, and said on Thursday that problems with marshals and backmarkers needed to be addressed.