McLaren's Jenson Button had a race littered with mistakes while Sebastian Vettel's one error cost the Formula One world champion victory at the Canadian Grand Prix on Sunday.

Vettel had looked ready to notch a sixth win in seven races until the 23-year-old German came under pressure from a hard charging Button on the final lap and made an uncharacteristic error allowing the Briton to rocket past and steal victory.

"We led every single lap except the last one, or one part of the last one," Vettel said.

"I made a mistake, it is clearly down to me.

"I locked up the rear a little bit ... I ended up in the wet and it was quite easy then for him to pass.

"It was a difficult day, easy to make mistakes ... but if you have got it in your hands and you give it away it is not the sweetest feeling."

Vettel still finished second ahead of Australian teammate Mark Webber in a chaotic race that was halted for more than two hours as rain lashed the Circuit Gilles Villeneuve.

Despite the appalling conditions, the young German drove a mature race, lead from the start and did not turn a wheel wrong until the final lap.

In stark contrast to Vettel's polished drive, Button was ragged and on the edge, squeezing teammate Lewis Hamilton into the wall and ending his race then colliding with Ferrari's Spanish double world champion Fernando Alonso.

But the Briton's daring was rewarded with a 10th career win while Vettel could only admit his mistake.

"I could feel Jenson was a little bit quicker than us, I could see Jenson was catching up," said Vettel. "Very difficult conditions -- one of the most challenging races this year.

"Overall I can be satisfied but at the moment the freshest impressions I have are being disappointed being in the lead all of the race.

"We were pushing very hard and sometime you make mistakes.

"I have no problem admitting that I went a little bit wide, outside the dry line so got away with second."

Vettel's second place finish still left him atop the standings with 161 points, 60 clear of Button.

"After a long afternoon and to have pretty much led every lap of the race, it was obviously frustrating to lose the Grand Prix almost in sight of the checkered flag," said Red Bull team principle Christian Horner.

"Unfortunately Sebastian made a rare mistake on a day when a lot of drivers made a lot of mistakes.

"He paid a price but second is still a good result and far from disastrous.

"We got a lot of points and Sebastian only 14 points off a maximum score after seven races, which is an achievement in itself."