Sebastian Saavedra capitalised on a mistake by Ryan Hunter-Reay to secure a surprise pole position for Saturday's inaugural IndyCar race on the Indianapolis Motor Speedway road course.
On a track still soaking from rain a few minutes earlier, Hunter-Reay had just claimed provisional pole when he lost the rear of his Andretti Dallara-Honda on the exit of the final corner, sending it into a long loop that ended with a heavy impact against the wall.
"Every time through there I had almost lost it," Hunter-Reay said. "In the wet you're always going for it, and there's a very fine line.
"The standing water was definitely an issue at times."
The Andretti driver escaped injury, but was docked his two fastest times from the session for causing the subsequent red flag.
That dropped him to third on the grid, and handed pole to KV driver Saavedra, who had moved into the top spot a short time earlier. It is the first IndyCar pole position of the Colombian's career.
"This is huge," he said. "It's a great way to start the Month of May. We saw there was a great opportunity and we took it, and I'm very proud of the team."
Simon Pagenaud will start from fourth and is the new track record holder after going quickest when the track was at its driest at the start of qualifying, while Will Power and Scott Dixon will line up from the third row, with both drivers being denied the chance to make a final run on new rubber by the red flag.
"It was our strategy to go out on older tyres at the start," said Power. "But you never know what is going to happen."
While Hunter-Reay (pictured) was the most visible victim of the rain, the changing conditions caught a number of drivers out.
Marco Andretti was among them; the Andretti driver using his tyres up early in the first qualifying phase in anticipation of showers, only to lose out when the track remained dry and his rivals' times improved.
There was also drama for Mikhail Aleshin, who had initially gone fast enough to progress from his group in the opening phase before he was issued a penalty for interference. That cost him his two best laps, which dropped him down the order and allowed Graham Rahal to progress in his place.
Pos Driver Team/Engine Time Gap 1. Sebastian Saavedra KV/Chevy 1m23.8822s 2. Jack Hawksworth Herta/Honda 1m24.0788s +0.1966s 3. Ryan Hunter-Reay Andretti/Honda 1m24.8882s +1.0060s 4. Simon Pagenaud Schmidt/Honda 1m25.2881s +1.4059s 5. Will Power Penske/Chevy 1m25.5216s +1.6394s 6. Scott Dixon Ganassi/Chevy 1m25.6548s +1.7726s 7. Sebastien Bourdais KV/Chevy 1m24.5187s Round 2 8. Juan Pablo Montoya Penske/Chevy 1m24.6209s Round 2 9. Tony Kanaan Ganassi/Chevy 1m24.7099s Round 2 10. Helio Castroneves Penske/Chevy 1m24.8839s Round 2 11. James Hinchcliffe Andretti/Honda 1m25.1318s Round 2 12. Graham Rahal Rahal/Honda 1m25.4748s Round 2 13. Marco Andretti Andretti/Honda 1m10.2488s Group 1 14. Ryan Briscoe Ganassi/Chevy 1m10.2261s Group 2 15. Josef Newgarden Fisher/Honda 1m10.3601s Group 1 16. Takuma Sato Foyt/Honda 1m10.2804s Group 2 17. Carlos Huertas Coyne/Honda 1m10.4264s Group 1 18. Justin Wilson Coyne/Honda 1m10.4141s Group 2 19. Carlos Munoz Andretti/Honda 1m10.5097s Group 1 20. Martin Plowman Foyt/Honda 1m10.4591s Group 2 21. Franck Montagny Andretti/Honda 1m10.5571s Group 1 22. Oriol Servia Rahal/Honda 1m10.5996s Group 2 23. Charlie Kimball Ganassi/Chevy 1m10.6413s Group 1 24. Mike Conway Carpenter/Chevy 1m10.6535s Group 2 25. Mikhail Aleshin Schmidt/Honda 1m11.2704s Group 2 All drivers use Dallara chassis