The RSports car came off worst, breaking its front left suspension, but Doornbos was spun to a standstill in turn one, and lost a lap waiting for the safety team to bump start him.
Ironically, that left the Dutchman still in ninth at the chequer – the same result that Bourdais had been subjected to after a brush with the Minardi car in Toronto – but Doornbos did benefit from his closest rival being forced to call it a day, Power completing just a handful more laps before deciding that it was too dangerous to continue.
Along with Tagliani, the Australian was the final retirement, leaving 13 cars to make it to the flag.
The final round of pit-stops passed off largely without problems, Bourdais resuming in front of Wilson and Rahal, with Pagenaud, Tracy and Junqueira completing the top six. Tracy and Junqueira had indulged in the most spirited battle of the closing stages, the Brazilian all over the back of his Canadian rival before ducking inside the Forsythe car at turn one – only to run wide on exit and allow Tracy back through.
Although they exited line astern after the third and final stop, Junqueira never had another opportunity, and even dropped behind Tracy's team-mate, Servia, by the chequer.
Bourdais, meanwhile, sailed serenely on to claim his second Edmonton win in the event's years, while the reigning champion, Wilson, chased him home, Rahal completed the podium – his second of the year – with Pagenaud doing all he could to uphold Team Australia's lead in the Triple Crown standings – a forlorn effort after Power's retirement.
Behind the Forsythe pair and Junqueira, Clarke, Jani and Heylen completed the unlapped runners, with Doornbos and the PCM duo all coming home a lap down.
The combined fortunes of the pre-race top three now means that Bourdais has resumed a familiar mid-season position, and heads to San Jose next weekend with a useful 20-point advantage over Doornbos, with Power a further five behind the Dutchman. Wilson, meanwhile, has moved further into contention and now trails Power by four points.
