"He's a master. Unfortunately for us, he's a master," declared rival team boss Frank Williams after the German overcame brake problems to win in Montreal for the sixth time on Sunday.

But even as he prepared to buy celebratory drinks for his team after taking the lead in the title race for the first time at the season's halfway point, Schumacher recognised that the battle was hotting up.

"The season is going to be a long one," he said after easing three points clear of McLaren's Kimi Raikkonen.

"We knew that from the beginning and we've sort of had confirmation by now and it will be a tough fight to the end."

Ferrari boss Jean Todt, whose team now lead both championships with Schumacher winning four of the last five races, agreed:

"We can expect the second half to be very tough because the opposition is very strong," he said. "We think we have all the elements in place to reach the targets we set ourselves at the start of the year."

Austrian Niki Lauda, a champion for both Ferrari and McLaren, praised Schumacher and said Montreal had hurt Raikkonen's chances.

The 23-year-old messed up when he went off the track in the decisive one-lap qualifying session, an error that forced him to start from the pitlane. Although he fought back from last to sixth, he still dropped potentially priceless points.

COSTLY ERROR

It was the third time this year that Raikkonen had started from the back, the last being in Spain.

"To make one mistake like he did in Barcelona is understandable for a young driver," said Lauda, who won the 1984 title for McLaren by half a point. "But this race here was bad for him because Michael is now in the lead.

"If you fight for a championship I know well that sometimes half a point decides it. So it was not good.

"But I am surprised that the Ferrari is not that much quicker (than the rest)," added Lauda.

"He (Schumacher) still has to fight like crazy because last year was easy compared to this year. But he's the most experienced, the cleverest and the quickest guy. And today he proved it again."

McLaren had a hard time but Williams could have hoped for more than Ralf Schumacher's second and Juan Pablo Montoya's third at a track that has favoured them in the past.

"At least the two of us were on the podium, which is great for the team, but Monaco and Montreal seem to work massively into our favour," said Ralf. "The next one is Nuerburgring, a totally different circuit.

"Just let's wait and see how we perform there before we think about pole positions and winning races again. But one thing is sure: The team has developed the car massively in the right direction.

"It's starting to pay off but we're still a long way away from where we really want to be."