McLaren were all set to take their first one-two for five years when Juan Pablo Montoya’s bad luck with backmarkers struck again.

The Colombian, who clashed with Tiago Monteiro to lose second in Turkey, was hit by Williams’ Antonio Pizzonia, denying him second place again.

That lifted Fernando Alonso up to a fortunate second – half a minute down on Raikkonen – and left the championship leader 25 points clear with just three races and 30 points up for grabs.

Jenson Button scored his second podium of the season with third place after an eventful race for the BAR-Honda driver.

The Englishman struggled initially on the wet track but as the water evaporated he found his speed and surged through the field late in the race and took advantage when Montoya his trouble.

Mark Webber kept clear of trouble to snatch fourth place for Williams with Rubens Barrichello taking advantage of the changing conditions to net fifth place for Ferrari.

Jacques Villeneuve scored sixth for Sauber with Ralf Schumacher’s Toyota seventh and Jordan driver Monteiro claiming an unlikely point for eighth.

At the start, Montoya held his pole position advantage while Raikkonen’s slow getaway meant he nearly lost second to Jarno Trulli.

Button made a flying start to creep up to sixth from eighth on the grid but team-mate Sato dropped him down a spot at the end of lap one.

Button was struggling badly in the tricky conditions and his challenge faded away with Ralf Schumacher passing him on lap seven.

Giancarlo Fisichella, who had charged through the field from 13th on the grid, soon caught Button but his gutsy fightback was ended on lap 11 when he lost the rear of his Renault through Eau Rouge, spinning him around and hard into the barriers.

That brought out the safety car and all drivers immediately darted into the pits, some returning a lap later after their gamble on dry tyres failed.

In the confusion, Ralf Schumacher passed Raikkonen for second but his brother Michael endured worse luck.

Takuma Sato slammed into the back of his Ferrari under braking, eliminating both cars and prompting the outgoing world champion to angrily lecture the Japanese.

Button moved back into the points with a superb move around the outside of Villeneuve on lap 24, just seconds before Schumacher pitted from second.

Toyota took a gamble to put the German on slick tyres but that backfired when he spun at Les Combes on his out lap, prompting him to revert to wet tyres with a costly second trip to the pits.

Raikkonen clocked a string of fastest laps to move to within striking distance of Montoya, and the Finn took the lead when his team-mate pitted on lap 33.

Two quick laps later he made his own stop and had pulled out sufficiently to emerge from the pits well clear of Montoya.

Jarno Trulli crashed his Toyota out of the race seconds later before Montoya was hit by Pizzonia three laps from the end.