Schumacher fears Button could be his undoing

World champion Michael Schumacher believes Britain's Jenson Button will pose the biggest threat to him maintaining his near-perfect record this season at Sunday's Canadian Grand Prix.

With the exception of Monaco, where he crashed, Schumacher has proved unbeatable in 2004, winning the other six grands prix in convincing style.

The German holds a 14-point lead over Ferrari team-mate Rubens Barrichello, with Button a further eight points adrift.

Button has claimed five podium finishes in his BAR this year and although the team do not have a good record at the Circuit Gilles Villeneuve, this time the track should suit their cars.

Schumacher, who won last year's Canadian Grand Prix despite brake problems, reckons the circuit is similar to Imola, where 24-year-old Button grabbed pole position and finished second in the San Marino Grand Prix.

"There are greater challenges on the calendar but you still have to prepare correctly for this track," Schumacher said.

"With it being a stop-go circuit, the brakes are understandably very important. Last year we had quite a few problems, but we have done our homework and we should go better this time.

"But I am assuming BAR are going to be very strong here because Montreal is a similar track to Imola, where they were extremely strong. We can expect another good fight."