Alex Tagliani set the fastest time in the only practice session before qualifying for the first of the two IndyCar races at Detroit's Belle Isle street circuit this weekend.
The Canadian moved to the top late in the session with a best lap of 1m18.2096s, which proved just enough to keep him ahead of Scott Dixon, who jumped up to second with his final lap.
Josef Newgarden was third-fastest ahead of Will Power, who had occupied the top spot for most of the morning.
Mike Conway, making his first appearance in the second Dale Coyne entry, finished an impressive fifth-quickest.
Preparations for qualifying were severely disrupted by six stoppages during the session, with 30 of the 75 allocated minutes of track time being lost to red flags.
Most were for harmless spins, although James Hinchcliffe's Andretti car sustained very minor damage when he lost the rear at Turn 1 and swiped the wall.
The lengthiest stoppage was also the most unusual, with the cars having to be taken off the track after a family of ducks found its way onto the circuit. A chase ensued before track workers were able to relocate the birds to a safer location.
Pos Driver Team/Engine Time Gap
1. Alex Tagliani Herta/Honda 1m18.2096s
2. Scott Dixon Ganassi/Honda 1m18.3168s + 0.1072s
3. Josef Newgarden Fisher/Honda 1m18.3612s + 0.1516s
4. Will Power Penske/Chevy 1m18.5808s + 0.3712s
5. Ryan Hunter-Reay Andretti/Chevy 1m18.5810s + 0.3714s
6. Mike Conway Coyne/Honda 1m18.7316s + 0.5220s
7. James Jakes Rahal/Honda 1m18.7745s + 0.5649s
8. Helio Castroneves Penske/Chevy 1m18.8473s + 0.6377s
9. Simon Pagenaud Schmidt/Honda 1m19.1253s + 0.9157s
10. Takuma Sato Foyt/Honda 1m19.1403s + 0.9307s
11. Justin Wilson Coyne/Honda 1m19.1965s + 0.9869s
12. EJ Viso Andretti/Chevy 1m19.2790s + 1.0694s
13. Marco Andretti Andretti/Chevy 1m19.3954s + 1.1858s
14. Sebastian Saavedra Dragon/Chevy 1m19.4059s + 1.1963s
15. James Hinchcliffe Andretti/Chevy 1m19.5819s + 1.3723s
16. Simona de Silvestro KV/Chevy 1m19.6043s + 1.3947s
17. AJ Allmendinger Penske/Chevy 1m19.7461s + 1.5365s
18. Graham Rahal Rahal/Honda 1m19.7990s + 1.5894s
19. Sebastien Bourdais Dragon/Chevy 1m19.8679s + 1.6583s
20. Ryan Briscoe Panther/Chevy 1m19.9024s + 1.6928s
21. Charlie Kimball Ganassi/Honda 1m19.9795s + 1.7699s
22. Tony Kanaan KV/Chevy 1m20.0110s + 1.8014s
23. Tristan Vautier Schmidt/Honda 1m21.2965s + 3.0869s
24. Ed Carpenter Carpenter/Chevy 1m21.9619s + 3.7523s
25. Dario Franchitti Ganassi/Honda 1m21.9985s + 3.7889s
All drivers use Dallara DW12 chassis