Jenson Button's hopes of putting a spoke in the wheel of Michael Schumacher's bid for a seventh Formula One world title foundered inside 11 laps of the San Marino Grand Prix.

The daunting Schumacher eventually clinched a comfortable fourth win of the season to maintain his 100% record, giving the Ferrari star a maximum 40-point haul, extending his lead in the so-far one-sided championship to 16 points to team-mate Rubens Barrichello.

Button at least scored his best result of his 71-race career by claiming the runner-up spot in his BAR to follow on from his third-place finishes in the last two grands prix in Malaysia and Bahrain.

A maiden victory surely cannot be too far away for Button, who at least did everything that was asked of him in starting from pole for the first time in Formula One once the red lights disappeared to signal what could be the last race at an out-dated Imola.

The 24-year-old made a clean getaway, leaving Schumacher in his wake and embroiled in a first lap dust-up with old adversary Juan Pablo Montoya in his Williams-BMW.

The two bitter rivals ran neck and neck at one point before Schumacher eventually held sway, forcing the Colombian to run wide at Tosa, leaving the 28-year-old to battle with team-mate Ralf Schumacher.

The duel allowed Button to pull away, but by the end of lap nine it became clear he had been running a light fuel load in setting his qualifying lap of one minute 19.753 seconds yesterday, the fastest seen at the 4.933km track.

Button was one of the first drivers in, allowing Schumacher a clear run and the 35-year-old German used all his experience to put in two punishing laps before he also pitted on lap 11.

After the first pit-stop shake-up, Schumacher had opened up a six-second cushion on the determined Briton, which for all intents and purposes signalled the end of the race.

What followed was a processional drive in the park for Schumacher, just as in Australia, Malaysia and Bahrain, but on this occasion in front of the adoring tifosi, Ferrari's loyal band of followers.

With just 10 laps remaining, Schumacher held a 28-second cushion to Button before he finally started to ease down, ultimately finishing an easy 9.7-second winner.

Button's second place in the race was not enough to move him ahead of Barrichello in the drivers' championship, the Brazilian taking sixth to leave him on 24 points and one point clear of the Briton.

Montoya claimed third to hold onto his fourth spot in the drivers' race, but is now 22 points behind Schumacher with the Renaults of Fernando Alonso and Jarno Trulli fourth and fifth.

Ralf Schumacher came home seventh, with Kimi Raikkonen in his McLaren eighth courtesy of Button's BAR team-mate Takuma Sato suffering an engine blow-out just five laps from the end when he looked on course to clinch the last point.

It was a remarkable first point of the season, though, for the Finn as he had started at the back of the grid after suffering an engine problem in qualifying.

David Coulthard finished 12th in the second McLaren, primarily due to a stop for a new nose cone at the end of the first lap after ploughing into the back of Alonso.

The positions of Alonso and Ralf Schumacher are under investigation, however, after the two drivers tangled on lap 50, with the Spaniard running into the side of the German at the tight Tosa corner.

"I was able to excite all the supporters, the tifosi," said Schumacher.

"It's just a dream come true to come here after a successful first three races and deliver a dream result, with the exception of qualifying. There's a lot of emotion."

But Montoya was not happy with Schumacher's tactics when he was pushed onto the grass at Tosa, with the duo coming together.

"He hit me hard enough to put me onto the grass and I will be surprised if he gets away with it," said an incensed Montoya, with Schumacher sitting alongside him.