Ryan Hunter-Reay took his first victory of the year in a rain-delayed IndyCar race at Milwaukee.
Rain showers half an hour before the scheduled start time forced a 90 minute delayed to allow the weather to improve and the track to be cleared.
Once things got underway Hunter-Reay was in contention from the opening stages, but he only took the lead for the first time when Helio Castroneves slowed on lap 141. From there he survived a series of late cautions to cross the line 5.1029s clear of nearest challenger Tony Kanaan.
Andretti's James Hinchcliffe secured third with a pass around the outside of Dreyer and Reinbold's Oriol Servia just a handful of laps before the end, elevating himself to second in the points standings in the process. EJ Viso (KV Racing) and Castroneves (Penske) rounded out the top five.
Polesitter and early race leader Dario Franchitti was among those whose afternoon ended early.
The Scot was running alongside Penske's Ryan Briscoe on a restart when the pair touched wheels. With what the Ganassi team suspects was broken suspension, Franchitti was entering the next corner when the car suddenly swapped ends and shot into the wall.
Team-mate Scott Dixon also had a frustrating afternoon, having climbed from 21st to third when he was called in for a drive-through penalty for jumping a restart - a decision that caused some consternation on the Ganassi pit perch, given that the restart in question was waved off.
The one scrap of consolation for the New Zealander was the fact that despite the penalty he was still able to finish one place ahead of title rival Will Power, who spent most of the race in a fruitless search for some clear air.
The only multi-car incident in the race occurred when Takuma Sato lost control and managed to collect James Jakes on his way into the wall, just as JR Hildebrand simultaneously shut down with a terminal overheating problem.
Last weekend's Texas winner Justin Wilson also failed to see the finish line after his engine let go with a cloud of smoke shortly before half-distance.
Pos Driver Team/Car Time/Gap 1. Ryan Hunter-Reay Andretti DW12-Chevy 1h52m17.8119s 2. Tony Kanaan KV DW12-Chevy + 5.1029s 3. James Hinchcliffe Andretti DW12-Chevy + 7.2715s 4. Oriol Servia Dreyer & Reinbold DW12-Lotus + 9.8940s 5. EJ Viso KV DW12-Chevy + 10.0782s 6. Helio Castroneves Penske DW12-Chevy + 12.1105s 7. Alex Tagliani Herta DW12-Chevy + 12.3440s 8. Ed Carpenter Carpenter DW12-Chevy + 12.7396s 9. Graham Rahal Ganassi DW12-Honda + 13.3395s 10. Rubens Barrichello KV DW12-Chevy + 13.8178s 11. Scott Dixon Ganassi DW12-Honda + 14.3764s 12. Will Power Penske DW12-Chevy + 24.2642s 13. Simon Pagenaud Schmidt DW12-Honda + 1 lap 14. Ryan Briscoe Penske DW12-Chevy + 1 lap 15. Marco Andretti Andretti DW12-Chevy + 1 lap 16. Mike Conway Foyt DW12-Honda + 1 lap 17. Charlie Kimball Ganassi DW12-Honda + 1 lap 18. Katherine Legge Dragon DW12-Lotus + 5 laps Retirements: Dario Franchitti Ganassi DW12-Honda 193 laps Takuma Sato Rahal DW12-Honda 107 laps James Jakes Dale Coyne DW12-Honda 106 laps JR Hildebrand Panther DW12-Chevy 105 laps Justin Wilson Dale Coyne DW12-Honda 93 laps Simona de Silvestro HVM DW12-Lotus 62 laps Josef Newgarden Fisher DW12-Honda 48 laps