Ferrari's Michael Schumacher fears Jenson Button's BAR could stand between him and yet another Formula One record in Canada on Sunday.

Seven will be the key number for the six-times world champion in Montreal, Schumacher seeking his seventh win of the season to become the first driver to win the same Grand Prix seven times.

The German, who won last year despite a brake problem, sounds confident enough heading into the first of two back-to-back races in North America, with the U.S. Grand Prix at Indianapolis on June 20.

But he also believes that high-flying BAR, ready to unleash a lighter and more powerful Honda engine, could pose more of a threat than ever.

"Last year we had to overcome a few problems but we did what we had to," said Schumacher. "I think that this year it will go even better.

"BAR could also do well here as Montreal is similar to Imola, where they showed their potential...it will be a tight race."

Schumacher has been the man to beat in Montreal for more than a decade, favoured more than anyone else at a circuit named after local hero and late Ferrari great Gilles Villeneuve.

The German has failed to finish only twice in 12 Canadian outings and has won three times in the last four years including the last two.

"There are probably more demanding circuits in the calendar but even so, I would always choose to race in Montreal," said Schumacher.

BAR CHALLENGE

Button has been on the podium five times in seven races and took pole position at the San Marino Grand Prix in Imola, finishing second.

Team mate Takuma Sato started the last race on the front row, a first for a Japanese driver, and needs just four more points to set a benchmark as his country's highest scoring Formula One driver.

A first win for BAR, a team built around Canadian former champion Jacques Villeneuve and only now coming good after five years of over-spending and under-performance, could even be on the cards.

"The step with the engine should be an improvement for us," said Button, who has yet to finish in the top 10 in Canada. "We know it's going to be quick but we don't know by how much yet.

"My aim is to get on the podium and this is a race I would love to win, given the chance.

"I think we'll be even closer to Ferrari over the next few races and that means we'll be closer to our dream, which is to win," added the 24-year-old Briton.

Renault, second overall, are the only team to have beaten Ferrari this year and should score points again while Williams are hoping for signs of improvement after a disappointing start to the season.

The circuit, one of the fastest in Formula One and considered a car-breaker, has been good to them before with Ralf Schumacher winning in 2001 and finishing runner-up last year.

"Following (the) tests at Silverstone and Monza, I'm convinced that we have made a step forward but I don't know how big this will be," said Ralf last week.

McLaren's Kimi Raikkonen has always finished in the top six in Canada but anything will be a bonus for the struggling team, with just five points so far, as they look forward to the introduction of a new car when they return to Europe.