Ryan Hunter-Reay led Marco Andretti across the line for an Andretti Autosport 1-2 in a rain-delayed and shortened IndyCar race at Barber.
A late spin into the tyres by Mikhail Aleshin meant that Hunter-Reay had the luxury of crossing the finish line under yellows, although he had been in control of the race ever since capitalising on a spin by Will Power to take the lead on lap 16.
Scott Dixon finished third, giving the Kiwi his fifth podium finish in as many starts at the Alabama circuit.
"It was definitely an interesting race," Dixon said. "We seemed to burn the front tyres up pretty quickly and had to fight back, but we just didn't have enough for Marco."
Thunderstorms in the lead-up to the scheduled start time resulted in a delay that extended to more than two-and-a-half hours, and when the race finally got underway it had been trimmed to an abbreviated 100-minute timed event.
The entire field started on wets before taking advantage of a caution to change to slicks almost in unison, although Hunter-Reay admitted that the early laps on the new tyres were an ordeal.
"That was horrible," he said. "It was awful for everybody. It was like being on an ice skating rink in sneakers".
The one outlier was Sebastian Saavedra, who gambled on staying out for a long stint on the wets, but while the strategy allowed the Colombian to lead a few laps, he faded back as the race progressed.
Power, meanwhile, eventually finished fifth behind Simon Pagenaud, but if he was annoyed at being caught out by the conditions, then he at least had plenty of company.
Juan Pablo Montoya was making extraordinary progress through the field early on before spinning into the gravel and losing two laps, while Carlos Munoz's race was ended by a similar spin.
Aleshin's accident followed an earlier incident in which he was turned around by Sebastien Bourdais, who earned a stop-go penalty as a consequence.
It was also a frustrating afternoon for Helio Castroneves, who was issued a drive-through penalty after mistaking Justin Wilson's crew for his own and stopping in the wrong pit box.
Results - 69 laps Pos Driver Team/Engine Time/Gap 1. Ryan Hunter-Reay Andretti/Honda 1h40m43.3337s 2. Marco Andretti Andretti/Honda +1.0364s 3. Scott Dixon Ganassi/Chevy +1.4286s 4. Simon Pagenaud Schmidt/Honda +2.4350s 5. Will Power Penske/Chevy +3.1559s 6. Justin Wilson Coyne/Honda +3.7009s 7. James Hinchcliffe Andretti/Honda +4.6538s 8. Josef Newgarden Fisher/Honda +5.3417s 9. Tony Kanaan Ganassi/Chevy +6.2513s 10. Charlie Kimball Ganassi/Chevy +6.8371s 11. Ryan Briscoe Ganassi/Chevy +7.6182s 12. Jack Hawksworth Herta/Honda +8.5257s 13. Takuma Sato Foyt/Honda +9.6750s 14. Mike Conway Carpenter/Chevy +10.1933s 15. Sebastien Bourdais KV/Chevy +11.3198s 16. Carlos Huertas Coyne/Honda +12.8894s 17. Graham Rahal Rahal/Honda +13.7182s 18. Sebastian Saavedra KV/Chevy +14.0955s 19. Helio Castroneves Penske/Chevy +16.1476s 20. Oriol Servia Rahal/Honda +1 lap 21. Juan Pablo Montoya Penske/Chevy +1 lap 22. Mikhail Aleshin Schmidt/Honda +6 laps Retirement/not classified Carlos Munoz Andretti/Honda 40 laps