Justin Wilson claimed his first win in the IRL IndyCar Series in Detroit after Helio Castroneves was ordered to relinquish the lead by race control having allegedly blocked the Newman/Haas/Lanigan driver.
Until the controversial late call by the officials, Castroneves looked set to take his third win at the Detroit street course and carve into title rival Scott Dixon's championship lead. With Dixon only finishing fifth, Castroneves has still reduced his deficit, but the title is now Dixon's to lose at Chicagoland next week.
Dixon and Castroneves had stormed away from the field in unison in the opening stages, pulling out a huge lead over the rest of the pack.
But when Dixon's Ganassi teammate Dan Wheldon - who had made a tactical early stop - tangled with Conquest's Jaime Camara and caused a yellow on lap 17, Dixon chose to make his first pit stop while the majority of the field stayed on track.
That dropped Dixon to 18th place, and as the Kiwi made slow progress through the midfielders, Castroneves stormed away from KV's Oriol Servia, Wilson and Andretti Green's Tony Kanaan at the front of the field.
By the time Castroneves made his own first stop under green on lap 30, his advantage was such that he was able to rejoin still ahead of Dixon, whose traffic delays meant that he was back in fifth place once all the front-runners had pitted.
Dixon would remain there for the rest of the afternoon, while Castroneves comfortably pulled away after every yellow and at one stage led by a full 16 seconds.
However when separate incidents for Wheldon and Mario Moraes (Dale Coyne Racing) caused the final caution with 25 laps to go, the pack was able to close back in on Castroneves.
Wilson had passed Servia for second in the pits and he launched an immediate attack on Castroneves when racing resumed. The Brazilian held on to the lead, but his defensive tactics attracted the ire of the race officials, and he was ordered to allow Wilson past. He duly obeyed the instruction, allowing Wilson to sweep ahead on lap 73.
Despite Castroneves' best efforts, Wilson was able to cruise home and clinch his first win since joining N/H/L and moving to the IndyCar Series, with the furious Castroneves having to settle for a close second place - putting him 30 points behind Dixon going into the finale.
They finished comfortably clear of third-placed Kanaan, with Servia holding off Dixon for fourth. Ryan Hunter-Reay (Rahal Letterman) completed the top six.
Bruno Junqueira used great strategy and some bold passes to move up from the back of the grid to seventh for Dale Coyne Racing, ahead of KV's Will Power, who lost ground when he damaged his front wing on Hunter-Reay's car, and Ryan Briscoe (Penske), who became caught in traffic having followed the same pit strategy as Dixon.
This pit plan also backfired for Wilson's teammate Graham Rahal, who dropped back from sixth to 13th when he had to make a late extra fuel stop. That allowed Vision Racing's AJ Foyt IV to fill the final top ten spot.
Other incidents saw EJ Viso crash out alone when on course for a top eight finish, Vitor Meira and Danica Patrick spoil their races with a collision, and Marco Andretti's uncompetitive weekend end in a gearbox failure.
Tomas Scheckter never had a chance to feature after his Luczo Dragon car broke a half-shaft on the opening lap, but he was able to rejoin following a long stop for repairs - as did debutant Alex Tagliani, whose Conquest Dallara had gearbox problems in the early stages.
Pos Driver Team Time 1. Justin Wilson Newman/Haas/Lanigan 87 laps 2. Helio Castroneves Penske + 4.4058 3. Tony Kanaan Andretti Green + 17.6815 4. Oriol Servia KV + 26.5468 5. Scott Dixon Ganassi + 27.7185 6. Ryan Hunter-Reay Rahal Letterman + 28.2688 7. Bruno Junqueira Dale Coyne + 28.6815 8. Will Power KV + 28.8776 9. Ryan Briscoe Penske + 35.5244 10. AJ Foyt IV Vision + 38.1040 11. Hideki Mutoh Andretti Green + 38.3811 12. Darren Manning Foyt + 44.4662 13. Graham Rahal Newman/Haas/Lanigan + 47.8028 14. Ed Carpenter Vision +1:01.2770 15. Mario Moraes Dale Coyne + 1 lap 16. Danica Patrick Andretti Green + 1 lap 17. Vitor Meira Panther + 4 laps 18. Marco Andretti Andretti Green + 6 laps 19. Buddy Rice Dreyer & Reinbold + 11 laps 20. Dan Wheldon Ganassi + 23 laps 21. Tomas Scheckter Luczo Dragon + 31 laps 22. Alex Tagliani Conquest + 33 laps 23. Milka Duno Dreyer & Reinbold + 41 laps 24. EJ Viso HVM + 55 laps 25. Jaime Camara Conquest + 71 laps