Scott Dixon took another major step towards his second IndyCar Series title by taking a record-equalling sixth win of the season at the Kentucky Speedway, but had to hunt down main rival Helio Castroneves on the final lap to come out on top.
The Kiwi, who had started from pole, appeared to be the man to beat all evening, but was a long way behind Castroneves with four laps to run as the race turned into a battle of wits over fuel. With relatively few yellows to interrupt the flow, the Penske team took the decision to top off Helio's load during the third and final caution, giving him the potential to run to the flag while the majority had to make a splash 'n' dash in the closing moments.
Despite an early challenge from team-mate Dan Wheldon at the green flag, Dixon held the upper hand through to lap 45, when he was passed by the rapid Vitor Meira, the Brazilian having dogged the Ganassi car's tyre tracks for the opening quarter of the race. Meira's lead was short-lived, however, for the Panther Racing team again proved less than a match for Ganassi in the pits, with Dixon regaining the point after managing to stretch his fuel a further lap.
Wheldon also beat Meira off pit-road, the pair having stopped together on lap 51, but had nothing for his team-mate after a brief look at top spot in traffic on lap 59.
At this point, neither Castroneves or fellow Brazilian Tony Kanaan had shown anything like front-running potential, occupying spots outside the top ten as they struggled to get their cars handling as they wanted. Both, however, made adjustments at the first opportunity, and gradually came back into contention.
Instead, the chasing pack was headed by AGR duo Marco Andretti and Hideki Mutoh, with Ed Carpenter and Ryan Briscoe also looking racy through the first half of the race.
Dixon continued to lead when the second caution of the race was called for debris following a clash between duelling dames Sarah Fisher and Danica Patrick. Fisher appeared to be at fault, coming down on her rival prematurely heading into turn three, but neither car was terminally damaged.
The ensuing yellow, however, allowed the majority of the field to pit for fuel and tyres, with Dixon again heading the race off pit-lane while Hunter-Reay spun while avoiding a potential clash with Buddy Rice. At the restart, Wheldon quickly dropped behind Andretti, as the #26 began a charge that would keep him in contention until the closing stages.
Like Meira before him, however, Marco was easily able to stay with the leader, but found it hard to make the pass that would give him the advantage, bobbing in Dixon's wake until lap 121, when the Kiwi's spotter failed to notify him about the off the pace Enrique Bernoldi emerging from the pits. Dixon found himself having to lift to avoid the Brazilian, allowing Andretti, who was on a higher line, to slingshot into the lead, and Wheldon, who was keeping tabs on the lead battle, to assume second place.