Kiwi Scott Dixon became the first back-to-back winner of the season by winning the first of Toronto's double-header IndyCar races.
Surviving an eventful race, Dixon seized upon Frenchman Sebastien Bourdais (Dragon Racing) with eight laps to go after the pair had waged an intense battle.
Dario Franchitti filled the final podium spot for what was to be a double podium for Ganassi before a sensational post-race sequel.
Franchitti was stripped of the position as the podium celebrations were beginning when he was handed a time penalty for blocking Will Power on the final lap.
The Scotsman was re-classified in 13th position with Marco Andretti promoted to third.
Power, who had led the race earlier, was having a solid run before his pass underneath Franchitti going into turn 3 forced him to lock the brakes and slide in front of the Ganassi driver before missing the corner and banging into the outside tyre wall.
Stewards however deemed that Franchitti had intentionally blocked Power in the lead up to the Toowoomba driver's miscued pass. Power was eventually classified in 15th place.
Franchitti was scathing when he was informed of the penalty at the end of the podium celebrations saying: “sometimes I just don't understand race control.”
Dixon's victory moves him to fourth on the list of all-time winners in IndyCar racing with 31 wins.
In the closing stages Dixon, with the benefit of having one push-to-pass remaining to help fend off any challenges from behind, quickly extended his lead to over 3s.
However a full course caution with four laps remaining after an incident involving Alex Tagliani neutralised the advantage to set up a grandstand finish.
When the green-white-chequered was flown Dixon bounded clear, leaving Bourdais in his wake.
Aussie Ryan Briscoe suffered a broken wrist after a late race incident when two cars collided in front of his Panther car. Briscoe is out of the second race in Toronto but is confident of a speedy recovery.
Meanwhile Takuma Sato has received a five-race probationary period after running into Ryan Hunter-Reay in the pitlane at the previous race at Pocono.
See below for full Race 1 result
|Simona de Silvestro