AJ Allmendinger sliced into Sebastien Bourdais' championship lead with a convincing win in Sunday's Bridgestone Grand Prix of Denver, a race that started and finished with a bang.

Aided by two recent Champ Car instigated 'variables,' the Push to Pass button and the Bridgestone option tyre, a mere 16 Champ Car World Series contenders put on a highly entertaining 97-lap race around Denver's 1.657-mile street circuit despite mechanical and accident related bothers reducing the field to eleven runners before the race had reached one-thirds distance.

Allmendinger was able to motor through the unfolding drama around him quite serenely once he had caught and passed polesitter Bourdais for the lead as the Frenchman struggled on the red-walled option tyres that would prove a bugbear for several drivers over the course of the day.

As the race entered its second half Allmendinger held a commanding lead over his Forsythe Racing teammate Paul Tracy, who had recovered magnificently from an opening turn dust-up with none other than Alex Tagliani, who was last seen trying to punch his fellow Canadian in San Jose. However the majority of the drama was still to come.

Tracy had grabbed second with slightly under 40 laps remaining from RuSPORT's Justin Wilson, who was left with the highly undesirable option tyres for his final stint and while a chase of Allmendinger was out of the question a Forsythe 1-2 looked very possible.

The Forsythe 1-2 looked like a reasonable bet right until the final lap, by which time a recovering Bourdais had latched firmly on to Tracy's rear wing. After slipping from first to fifth inside five laps earlier in the race Bourdais had been on fire ever since the option tyres were replaced with Bridgestone's regular compound and made short work of a helpless Wilson and an understandably co-operative Bruno Junqueira in the sister Newman-Haas entry.

After cutting into Tracy's advantage in the final five laps Bourdais drove around the outside of Tracy on the back straight on the last lap only to have Tracy try and regain the position on the inside heading into the invitingly wide final corner with disastrous consequences. The rear end of Tracy's car came around, knocking Bourdais into the air and breaking Tracy's front suspension. Although both tried, neither could get their cars across the finish line and instead of being classified second and third Tracy was listed in sixth place and Bourdais seventh.

To top things off Bourdais then marched across the track while cars were still racing to the finish line to confront Tracy, giving the Canadian driver a couple of shoves before stalking off to the safety vehicle.

In the midst of all this drama, Allmendinger celebrated his fourth win of the year while Junqueira nipped through to take second. As pleased as Junqueira was, his delight paled in comparison to that of Briton Dan Clarke, who battled past Will Power, Charles Zwolsman and his teammate Nelson Philippe before breezing by his countryman Wilson for what became third place on the final corner.

Power and Philippe completed a strange looking top five while Wilson was classified in eighth after falling off the lead lap late in the race and being unable to take advantage of Bourdais and Tracy's late fiasco.

Katherine Legge ended a trouble-free day in ninth place with Zwolsman and Jan Heylen completing the runners.

Tagliani's opening lap demise was followed in quick succession by mechanical problems for Oriol Servia, Andrew Ranger and Mario Dominguez, all of whom could have finished on the podium had their cars held together but after Nicky Pastorelli's lap 27 departure, thankfully everyone else kept running right until the final half mile.

In the points table Allmendinger moves back into second place behind Bourdais with a deficit of 32 points with Wilson a further three marks back in third place.