The race got off to an abortive start when Justin Wilson got loose off turn 3, lost the back end and went into the wall, collecting the completely innocent Mario Moraes on the way. Both drivers were okay, but bitterly disappointed to be out so quickly.
Polesitter Will Power led the race initially but came under increasing pressure from Marco Andretti who was running fast at this point. Power held him off, helped by coming up on traffic in the form of Milka Duno who was abysmally slow: caught seemingly by surprise by Power diving down the inside, they touched and Duno overcorrected up the track and right into the path of the pursuing Andretti, who reacted quickly to avoid running into the back of her. A few laps later, Duno was black flagged for being too slow and ordered to the pits,
That enabled Power to continue in the lead through to lap 33, at which point Andretti finally got in front. Power may have been feeling the effects of his contact with Duno, and he started to fall back during the next few laps and seemed to be struggling, not helped by almost running into the back of another slow backmarker Bertrand Baguette. Up front, Andretti managed to hold the lead for a mere 13 laps by which point Dario Franchitti was ready to take command; after this Andretti would suffer from escalating handling problems with culminated in an urgent out-of-sync green flag pit stop to dial in more front wing.
The second caution of the afternoon came out on lap 51 for debris on the front stretch, and the cars had the welcome opportunity to come into the pits for fuel, tyres and tweaks. Franchitti won the race off pit road, but behind him there was a three-wide battle between Tony Kanaan, Helio Castroneves and Scot Dixon. Caught in the middle, Castroneves ended up pinching Dixon on the inside and there was contact, Castroneves briefly thrown up into the air in an impact that affected his steering. There were fears for Dixon's suspension as well, but they appeared unfounded: at the restart, Dixon took the battle straight to his Target Ganassi team mate and the duo had a thrilling spat over the lead which was only resolved when Franchitti took advantage of the opportunity of coming up on the slow Simona de Silvestro to get emphatic track position.
A third yellow on lap 95 came out when Sarah Fisher, trying to move out of the way of leaders coming up to lap her, ended up on the marbles an washing up the track into the wall. The pit stops were calmer this time (although jack problems for Simona de Silvestro led to her hitting one of her pit crew, earning a drive-thru penalty) with Franchitti, Dixon and Kanaan still the top three ahead of Ryan Hunter-Reay, Helio Castroneves and Takuma Sato at the restart.
The Ganassi team mates were immediately right back in hand-to-hand combat, Dixon gaining the initial advantage but allowing Franchitti to make an immediate strike back. The battle unsettled Dixon who dropped back to fourth, opening up an opportunity for team mates Kanaan and Hunter-Reay to take on Franchitti. Kanaan took the lead for nearly twenty laps - his first time in the lead since Chicagoland in 2009 - and while Franchitti found his way past again on lap 136, ten laps later Kanaan was able to wrest the lead back again in an extremely tough-but-fair battle between the old friends one one-time colleagues.
By this point Dixon was clearly in trouble from his earlier pit lane incident, falling back to seventh as Takuma Sato, Hunter-Reay, Castroneves and EJ Viso were able to pass him with comparative ease. It was the culmination of an excellent run for Sato who was up to third on lap 178, but he then came up on the back of Alex Lloyd and had the clean air taken off the front wing. That sent him into the marbles and then a one-way ticket into the wall at turn 4 that brought out the fourth yellow of the afternoon.
During the pit stops, Ryan Hunter-Reay locked up coming into his pit box and clipped the tyre waiting to go on the car in the pit box immediately behind him - which was Tony Kanaan. The delay cost Kanaan critical seconds and he emerged form the pits in third place, behind Franchitti and Helio Castroneves and just ahead of EJ Viso (picking up the baton from his fallen team mate Sato), Will Power and Scott Dixon in sixth; Hunter-Reay got handed a drive-thru for the tyre contact that left him two laps down.
Helio took advantage of his new track position on lap 196 by taking the lead with a great move on Dario - so much for any problems from that pit lane collision early in the afternoon! And then, abruptly, Dario was no longer a factor: he pulled down the track and coasted into the pits, a gearbox failure leaving him stuck somewhere between fifth and sixth gear.
That left the race a two-horse contest between Helio and Tony Kanaan. Helio pulled out a big lead and for a while it looked as though Kanaan simply didn't have anything to fight back with, but then with a dozen laps remaining the cars came up on traffic, and Kanaan used this and all the power boost at his disposal to cut Helio's lead in a flash and slingshot past the Penske car into the lead, and which point he raced away from Helio - who was struggling with tyre wear - at a rate of 0.4s a lap or more.
It was a famous victory for Kanaan, whose last visit to victory lane was in Richmond in June 2008, 34 races ago. Always a popular guy, everyone seemed genuinely delighted for the Brazilian, even his beaten compatriot Helio. And Andretti Autosports was thrilled to finally break the grip on the ovals of the Penske and Ganassi teams, and maybe - just maybe - open up the 2010 championship just a little.