World champion Lewis Hamilton and Jenson Button crashed out early on, although the Brawn man's championship lead was cut by only two points to 16.

The incident saw the safety car come out, after which Raikkonen used his power-boost button to take the lead.

Red Bull's title-chasing Sebastian Vettel finished in third at Spa.

The German started in eighth but posted the fastest lap of the race and leapfrogged team-mate Mark Webber in the drivers' championship into third place behind Button's team-mate Rubens Barrichello, who limped over the line in seventh place with a Mercedes engine that was close to blowing up.

BMW Sauber drivers Robert Kubica and Nick Heidfeld finished fourth and fifth respectively ahead of McLaren's Heikki Kovalainen.

Force India secured their historic first points in Formula 1 with Fisichella's second in dry, warm conditions in the Ardennes forest.

But the concertina-effect crash at the back of the chasing pack on lap one - in which Renault's Romain Grosjean appeared to clip Button causing Hamilton and Toro Rosso's Jaime Alguersuari to also hit the tyre barriers at Les Combes - handicapped the Italian.

After the safety car went back in on lap five following the incident which is being investigated by race stewards, Raikkonen easily accelerated past Fisichella out of Eau Rouge using a quick push of his Kers (Kinetic Energy Recovery System) button.

From that point on Fisichella pushed the Finn all the way and although he was the quicker driver he could not get ahead of Raikkonen over the remaining 39 laps.

"We were probably not the fastest in lap times but we managed to keep everybody behind," said 2007 world champion Raikkonen. "And that's enough."

Fisichella said it was a "great result" for a Force India team which caused an enormous shock on Saturday by qualifying on pole, but that he felt a tinge of regret at how the race panned out.

"Actually, I was quicker than Kimi," he added. "He only took me because of Kers at the beginning and I'm a little bit sad for that because I was keeping pace and exactly same strategy race.

"It's great for second. But actually we could have won the race."

Highlights - Raikkonen wins in Belgium (UK users only)

Raikkonen started sixth but made an immediate charge, swinging past the virtually-still Barrichello off the grid before going very wide into the run-off area at La Source to give himself room to use his Kers to speed past the BMW Sauber cars and move into second behind pole-sitter Fisichella.

But then came the crash, which changed the course of the race and also caused Button's first retirement of the season.

While the stumbling championship leader - who has now not finished on the podium in the past five races - stopped short of blaming Grosjean, he did question why the rookie French driver braked so late through the corner and insisted the incident was not his fault.

"It was an avoidable accident," he said. "It's really frustrating."

"I suppose it is [relatively] good that it happened here. Hopefully we can get back on track in the next race."

Kubica was close to landing a podium place for BMW Sauber, who have announced their intention to pull out of the sport, but Germany's Vettel slipped ahead of the Pole as he came out of the pits following the second stop in his Red Bull on lap 35.

source: bbc