Will Power took his fourth IndyCar win of the season in a typically incident-packed Toronto race, thanks to a late pass on long-time leader Justin Wilson. With Wilson then spinning, just half a lap after losing the lead to Power, Dario Franchitti came through to second, ahead of Ryan Hunter-Reay.

Dreyer & Reinbold driver Wilson had held his pole advantage through a serene opening stint, while Power was bundled back from second to sixth at Turn 1 behind his Penske teammate Helio Castroneves, Franchitti (Chip Ganassi Racing), Andretti Autosport's Hunter-Reay and Ganassi's Scott Dixon in the opening corners.

Power would re-pass Dixon before the leaders all pitted under the first yellow – caused by Mario Moraes squeezing his KV Racing teammate Takuma Sato into the wall – while Wilson would fall behind Castroneves, Franchitti and the recovering Power.

The field rejoined behind Paul Tracy (KV) and Vitor Meira (AJ Foyt Racing), who had both stayed out. Tracy would lead for 14 laps, but predominantly under yellow thanks to a string of incidents. First Castroneves clipped Meira and flew into the tires at the end of the Turn 3 escape road, then Alex Lloyd crashed his Dale Coyne car at Turn 1, then on the next restart attempt Moraes dived past Dan Wheldon (Panther) at Turn 3 and speared Mario Romancini's Conquest Dallara-Honda into the tires.

In one of the few moments of green flag racing between those incidents, Franchitti slipped past Tracy to reclaim the lead, and with both the Canadian legend and Meira finally making their stops under the fourth full-course caution, Franchitti, Power and Wilson were able to get on with some serious racing when the green flag flew again.

Franchitti was the first of the lead group to make his second and last pit stop 32 laps from the end, and it looked like a masterstroke as Power and Wilson then encountered traffic on their pit-in lap. However, both emerged ahead of Franchitti, and Dreyer & Reinbold got Wilson out in front of Power and back into the race lead.

He then pulled away rapidly, until another yellow with 20 laps to go. This time to pull Raphael Matos' De Ferran Dragon car out of the tires and bump start E.J. Viso (KV) who got embroiled in the Alex Tagliani (FAZZT Race Team)/ Matos collision. Meanwhile elsewhere on track Tracy had to be bump started after an overambitious passing attempt on Simona de Silvestro (HVM) saw him lock his brakes and slide into the Turn 3 escape road.

Disaster would strike for Wilson at the restart, as he slid sideways out of the final corner, giving Power a run toward Turn 1. The Penske driver swept around the Brit who continued to struggle with grip until finally at Turn 8, he looped into a 180-degree spin and tumbled to the rear of the pack.

Power then stayed ahead of Franchitti through one last yellow for Tomas Scheckter (Dreyer & Reinbold Racing) tangling with Tagliani, before inching away to secure his fourth win of 2010 and stretch his points lead still further. None of his rivals have scored more than one win yet.

Hunter-Reay came through to a third, surviving late contact while passing Dixon at Turn 3. The Ganassi car was pushed into the wall by the rear of the Andretti car, and suffered terminal suspension damage.

Tony Kanaan was fourth for Andretti Autosport, while Graham Rahal charged through to a superb fifth on his return to Newman/Haas Racing – despite drop-kicking Ryan Briscoe's Penske into the wall and causing the Aussie to pit for a new nose-wing section. Remarkably, Rahal's car suffered little damage in the incident.

Andretti Autosport got all four cars into the top eight, thanks to Danica Patrick's strong run to sixth ahead of Marco Andretti, who slipped to eighth on the last lap as a recovering Wilson salvaged seventh. De Silvestro got her best finish of the season with a strong run to ninth, while Tracy took 13th, and top KV car.

Pos  Driver               Team                    Time/Gap
 1.  Will Power           Penske             1h47m15.2554s
 2.  Dario Franchitti     Ganassi               +  1.2757s
 3.  Ryan Hunter-Reay     Andretti              +  1.7605s
 4.  Tony Kanaan          Andretti              +  3.5382s
 5.  Graham Rahal         Newman/Haas           +  9.7349s
 6.  Danica Patrick       Andretti              + 11.9439s
 7.  Justin Wilson        Dreyer & Reinbold     + 12.3783s
 8.  Marco Andretti       Andretti              + 16.3360s
 9.  Simona de Silvestro  HVM                   + 21.5321s
10.  Dan Wheldon          Panther               + 23.1537s
11.  Vitor Meira          Foyt                  + 25.8960s
12.  Hideki Mutoh         Newman/Haas           + 26.2878s
13.  Paul Tracy           KV                    +    1 lap
14.  Mario Moraes         KV                    +    1 lap
15.  Tomas Scheckter      Dreyer & Reinbold     +    1 lap
16.  Bertrand Baguette    Conquest              +    1 lap
17.  Alex Tagliani        FAZZT                 +    1 lap
18.  Ryan Briscoe         Penske                +   2 laps
19.  EJ Viso              KV                    +   3 laps

Retirements:

     Scott Dixon          Ganassi            71 laps
     Raphael Matos        De Ferran Dragon   64 laps
     Mario Romancini      Conquest           31 laps
     Alex Lloyd           Dale Coyne         26 laps
     Helio Castroneves    Penske             21 laps
     Takuma Sato          KV                 15 laps
     Milka Duno           Dale Coyne         8 laps