Indianapolis 500 winner Ryan Hunter-Reay opened this weekend's IndyCar double-header in Detroit by going fastest in Friday's first practice session on the streets of Belle Isle.
The Andretti driver was in the mix right through the session, and eventually claimed the top spot with a best lap of 1m18.8595s.
Justin Wilson leapt up to second fastest at the last moment with a time 0.0221s down on Hunter-Reay's, leaving Helio Castroneves just behind him.
Simon Pagenaud and Tony Kanaan both made late improvements to complete the top five, the pair squeezing in just ahead of last year's surprise winner Mike Conway, who had been the session leader just a minute or two earlier.
It was a quiet start to the weekend for some of the series' traditional frontrunners: Will Power and reigning champion Scott Dixon both finished the morning well outside the top 10, while Juan Pablo Montoya completed just 13 laps on his way to 22nd.
Despite some very loose cars and some spectacular catches - most notably one by Graham Rahal, who managed to gather up a particularly lurid slide five minutes from the end without hitting anything - the session was completed incident-free.
Pos Driver Team/Engine Time Gap Laps 1. Ryan Hunter-Reay Andretti/Honda 1m18.8595s 36 2. Justin Wilson Coyne/Honda 1m18.8816s +0.0221s 31 3. Helio Castroneves Penske/Chevy 1m18.8977s +0.0382s 49 4. Simon Pagenaud Schmidt/Honda 1m19.1652s +0.3057s 12 5. Tony Kanaan Ganassi/Chevy 1m19.2083s +0.3488s 45 6. Mike Conway Carpenter/Chevy 1m19.2454s +0.3858s 52 7. Ryan Briscoe Ganassi/Chevy 1m19.3029s +0.4434s 61 8. James Hinchcliffe Andretti/Honda 1m19.3325s +0.4730s 41 9. Graham Rahal Rahal/Honda 1m19.4933s +0.6338s 31 10. Charlie Kimball Ganassi/Chevy 1m19.7035s +0.8440s 41 11. Marco Andretti Andretti/Honda 1m19.7299s +0.8704s 30 12. Sebastian Saavedra KV/Chevy 1m19.7931s +0.9336s 55 13. Jack Hawksworth Herta/Honda 1m19.8421s +0.9826s 42 14. Scott Dixon Ganassi/Chevy 1m19.8807s +1.0212s 21 15. Carlos Munoz Andretti/Honda 1m20.0602s +1.2007s 30 16. Takuma Sato Foyt/Honda 1m20.1145s +1.2550s 18 17. Will Power Penske/Chevy 1m20.1190s +1.2595s 47 18. Mikhail Aleshin Schmidt/Honda 1m20.1811s +1.3216s 28 19. Josef Newgarden Fisher/Honda 1m20.2621s +1.4026s 42 20. Sebastien Bourdais KV/Chevy 1m20.4368s +1.5773s 41 21. Carlos Huertas Coyne/Honda 1m20.7621s +1.9026s 43 22. Juan Pablo Montoya Penske/Chevy 1m20.9527s +2.0932s 59 All drivers use Dallara chassis