Dario Franchitti claimed his second Indianapolis 500 victory with a commanding drive for Ganassi in the 2010 edition of the IndyCar Series' premier race.
Dan Wheldon finished in second place, as a late fuel stop meant Tony Kanaan had to relinquish the runner-up spot with just four laps to go after an epic drive from the back of the grid.
Alex Lloyd took a remarkable third place for Dale Coyne Racing - completing an all-British top three, although his position could come into question with Marco Andretti alleging he was passed under yellow.
Having dominated qualifying, Penske's race went awry due to pit incidents and strategy miscues, and the polesitting squad came away with just eighth and ninth.
The race ended under yellow as Mike Conway made contact with Ryan Hunter-Reay and had a massive accident. The Dreyer & Reinbold car rode over the back of Hunter-Reay's Andretti Autosport entry and flew into the fencing, where its back end was ripped off before it crashed back down onto the track. Conway is being flown to hospital with an injury to his right leg.
The yellow for that accident secured Franchitti's victory, for he went into the final lap marginal on fuel as all the frontrunners tried to stretch their final tank-load over nearly 40 laps.
Franchitti had been the fastest man throughout the race, leading the vast majority of laps and heading the field by a margin of up to 10s at times.
He moved from third to first within the opening turns of the race, and apart from a brief battle with Penske's Will Power early on, he only lost the lead to strategy vagaries.
With several drivers gambling on alternate strategies at the end, Franchitti was back in fifth going into the last 20 laps - but aware that none of those ahead had much chance of reaching the finish on their current fuel loads without a miraculously long yellow.
When Helio Castroneves (Penske) pitted eight laps from the end, Franchitti hit the front with Kanaan chasing him down. The Brazilian had flown through the field from his 33rd place start, but had not conserved sufficient fuel and had to pit with just four laps to go.
His stop moved Panther driver Wheldon into second after a quietly impressive surge up through the field. Marco Andretti looked set to at least salvage third for Andretti Autosport, but dropped to sixth in the confusion as the late yellow was called. The American was adamant that he was third when the caution happened and that the results should be amended.
But for now at least, Lloyd holds an incredible third position. The young Briton had been creeping towards the top ten with a very competitive race car, and as others backed off or pitted with fuel worries in the closing laps he gained place after place and found himself a shock third.
Scott Dixon (Ganassi) was never a victory threat and lost a lot of ground when he lost a front wheel in the pitlane, before finally recovering to fourth.
Danica Patrick looked set for a top 12 finish at best, until she too gained huge ground amid the late fuel and yellow confusion and crossed the line in fifth to become Andretti's top finisher.
The unfortunate Conway and his Dreyer & Reinbold team-mate Justin Wilson had both led in the closing stages as the squad tried an alternate fuel strategy, and while Conway's race came to a sad end in the crash with Hunter-Reay, Wilson was elevated to seventh as the mayhem unfolded.
Power and Castroneves were Franchitti's main rivals in the early stints, only for Power to pull away from a pitstop with his fuel hose still attached, and Castroneves to stall in the pits later on, which left them eighth and ninth in the end. The Brazilian briefly reappeared in the lead after pitting out of sequence but needed a lot more laps under yellow to make it to the finish. Ryan Briscoe crashed the third Penske entry just before three quarter distance.
Fazzt's Alex Tagliani ran in the top four at first, faded later and tumbled to 16th, before recovering to a fine 10th place ahead of the unfortunate Kanaan.
Qualifying stars Graham Rahal (Rahal Letterman) and Ed Carpenter (Vision) had frustrating races. Rahal pitted out of sequence to attend to handling problems, charged back into the top ten, received a penalty for blocking Wheldon, then got back up to third on a strategy gamble before having to pit on lap 189 as the yellow he needed failed to appear. He finished 12th, while Carpenter was a top five contender until a lack of fuel forced him to stop illegally in a closed pit.
A blocking penalty also dropped Townsend Bell (Ganassi/Schmidt) out of the top ten, while Tomas Scheckter led for a while thanks to a well-timed pitstop and looked capable of a top four finish for Dreyer & Reinbold before losing ground in the final stops. Both needed late splash and go stops too, dropping them to 15th (Scheckter) and 16th.
HVM's Simona de Silvestro was ultimately the highest-placed rookie in 13th, just beating Conquest's Mario Romancini as both all but ran dry on the last lap.
Several of the stars of the month were out before half-distance. There would be no fairytale for Bruno Junqueira, who crashed his Fazzt car after just seven laps. But he was not the first retirement - that unhappy honour falling to De Ferran Dragon's Davey Hamilton, who spun at Turn 2 on the very first lap and hit the inside wall.
His team-mate Raphael Matos showed excellent pace, charging up to third behind Franchitti and Castroneves before things went horribly wrong at his second pitstop, when a rear wheel became detached as he accelerated away, causing him to spin. The crew retrieved the car and Matos rejoined, only to crash heavily soon afterwards.
Top ten qualifier Hideki Mutoh struggled with handling problems from the outset and eventually parked his Newman/Haas car. Andretti Autosport's John Andretti crashed shortly after becoming the first man of the afternoon to be penalised for blocking Wheldon, debutant driver and team Sebastian Saavedra and Bryan Herta Autosport were just one lap down until a lap 159 crash, while Mario Moraes (KV), owner/driver Sarah Fisher and Vitor Meira (Foyt) saw their races ended by relatively minor impacts with the barriers. With EJ Viso stopping with handling issues, Takuma Sato was KV's only finisher in 20th after a difficult race on his Indy debut.
Pos Driver Team Gap 1. Dario Franchitti Ganassi 3h05m37.0131s 2. Dan Wheldon Panther + 0.1536s 3. Alex Lloyd Dale Coyne + 20.9876s 4. Scott Dixon Ganassi + 21.4922s 5. Danica Patrick Andretti + 21.7560s 6. Marco Andretti Andretti + 23.5251s 7. Justin Wilson Dreyer & Reinbold + 25.9761s 8. Will Power Penske + 30.2474s 9. Helio Castroneves Penske + 33.0137s 10. Alex Tagliani Fazzt + 34.2482s 11. Tony Kanaan Andretti + 59.5957s 12. Graham Rahal Rahal Letterman + 59.9739s 13. Simona de Silvestro HVM + 1m01.6745s 14. Mario Romancini Conquest + 1m05.0219s 15. Tomas Scheckter Dreyer & Reinbold + 1 lap 16. Townsend Bell Ganassi/Schmidt + 1 lap 17. Ed Carpenter Panther/Vision + 1 lap 18. Ryan Hunter-Reay Andretti + 2 laps 19. Mike Conway Dreyer & Reinbold + 2 laps 20. Takuma Sato KV + 2 laps 21. Ana Beatriz Dreyer & Reinbold + 4 laps 22. Bertrand Baguette Conquest + 17 laps Retirements: Sebastian Saavedra Herta 159 laps Ryan Briscoe Penske 147 laps EJ Viso KV 139 laps Sarah Fisher Sarah Fisher 125 laps Vitor Meira Foyt 105 laps Hideki Mutoh Newman/Haas 76 laps Raphael Matos De Ferran Dragon 72 laps John Andretti Andretti 62 laps Mario Moraes KV 17 laps Bruno Junqueira Fazzt 7 laps Davey Hamilton De Ferran Dragon 0 laps