Out front, pole man Kimi Raikkonen (McLaren) made a blistering getaway to lead, with Olivier Panis (Toyota) jumping ahead of the slow-starting Barrichello, while Ralf Schumacher did likewise to take third for Williams. By the end of lap one, Raikkonen had extended a 1.6sec lead, while team-mate David Coulthard pulled off a smart round-the-outside pass on Barrichello for fifth.

R Schumacher bombed past Panis on the start/finish straight on the following tour, but it was the second Williams, that of Montoya, that caught the attention. He lunged alongside Barrichello on the outside under braking, much like DC had a lap earlier. This time, however, Rubens stuck to his cause and they turned into the left-hander side-by-side. Montoya went for the inside of the following right-hander, so did Barrichello.

End result? Montoya's right-front wheel clipped Barrichello's left-rear, contact that sent Rubens spinning off into the gravel. Although he lost positions to both Renault, Montoya escaped – or so it seemed.

Rubens was indignant: "I know we've always said that we race each other quite close and that one day we might touch, but it shouldn't have been today. It was very close, but I didn't turn into him. I thought I had given him space. I hadn't even reached the apex of the corner, and then I felt a bang."

Six laps later, the world was informed that Montoya was 'under investigation'. It was at least another 10 minutes before his drive-through pit penalty, for causing an 'avoidable incident', was confirmed. To most observers, the only crime he seemed guilty of was attempting to overtake.

Montoya's day got better before it got worse, though. As rain began to fall, the Michelin dry weather tyres coped with the slightly greasy surface much better than the Bridgestone runners. M Schumacher fell back, although not before he appeared to pass Panis for third under the yellow flags required to tow his stranded team-mate out of the gravel trap. Behind him, Montoya pulled a similar move on Jarno Trulli for seventh.

Montoya passed Alonso and then title nemesis M Schumacher in quick succession, before storming his way up to Coulthard, who he passed at Turn 1 on lap 14 with a stunning manoeuvre. Michael had fallen back to sixth as the first pitstops approached, but things were about to go in his favour.

Just as his Ferrari trundled down the pit lane, the heavens opened. Ironically, the call had already been made to put a new set of dry tyres on the car, so he was back in on the next lap for wets, but this was when the race turned. Montoya suffered a fuel rig failure, which caused a 15sec pitstop, and then he had to serve his drive-through. He stayed out on dry tyres for far too long, slithering briefly off the track at Turn 9, before pitting for wets. He was now a lap down…

If that wasn't bad enough for Williams, confusion on the radio meant R Schumacher stayed out on dry tyres in the rain, only to slither off into the tyrewall as the team were shouting at him to pit. Talk about a double whammy, one that also sideswiped its constructors' championship hopes.

"We made some mistakes today," admitted chief operations engineer Sam Michael. "The rain was very difficult to forecast, but we should have done a better job." On the subject of Montoya's penalty, he said: "We abide by the stewards' decision."

Cars to benefit most in the rain were Jenson Button (BAR) and Heinz-Harald Frentzen (Sauber), not only because they were on the superior Bridgestone wet tyres, but because they had switched to them at their first pitstops. Button led for 10 laps, before the storming M Schumacher gobbled both he and Frentzen up. Michael had already demoted Raikkonen, sailing past him at Turn 9 and effortlessly pulling away.

Raikkonen had trouble making inroads into third placed Frentzen (thanks to his less grippy Michelin wets) until the track dried, and he was back on Michelin dry tyres as soon as possible. By then Button's car had expired with what was termed a hydraulic failure (well, the hydraulics would fail if the engine grenaded, wouldn't they?) and Kimi finally relieved second place off Frentzen on lap 54.

After that, hostilities subsided. Schumacher cruised to victory by 18secs over a rueful Raikkonen. Frentzen held third, while Trulli overcame the second Sauber of Nick Heidfeld in the latter stages to finish fourth. The much-delayed Montoya grabbed sixth from Giancarlo Fisichella's Jordan, but the points he scored weren't enough to keep him in the title fight and he left the track while the champagne on the podium was still flowing.

Ferrari's technical director Ross Brawn was ecstatic with the outcome: "The key to victory today was the weather. We're pretty overwhelmed about this victory, even though we called it wrong on the first pitstop. It would have been nice to finish the title here, so we've still got a lot of work to do."

Justin Wilson grabbed the final point for Jaguar after a gritty drive. His team-mate Mark Webber actually led during the rain chaos, but the Aussie stuffed his car heavily into the tyrewall soon after. Cristiano da Matta probably would have scored a point had he not pitted six times in his Toyota, while early frontrunner Panis had a dreadful first pitstop from which he didn't recover and he too stacked his car into a tyrewall.

The Minardis of Jos Verstappen and Nicolas Kiesa rounded out the 11 finishers. Everyone else was chalked up as the casualties of combat.

It was a battle that looks to have won the war for Schuey.