Ryan Briscoe took pole position at Chicagoland for the third straight year with a commanding qualifying run.
The Penske driver, who had also been fastest in practice, was nearly 0.2 seconds quicker than his nearest rivals on his two-lap run, as the series switched from a four-lap to a two-lap average for oval qualifying from this weekend.
Ganassi's Dario Franchitti will share the front row with Briscoe, while the polesitter's Penske teammates Will Power and Helio Castroneves lined up third and fourth.
But Franchitti is the only Ganassi man near the front, with Scott Dixon a deeply puzzled 15th at the end of the session.
Marco Andretti was the best of the Andretti Autosport quartet in fifth, while Newman/Haas' Graham Rahal and Hideki Mutoh took sixth and eighth, split by a good run from Dan Wheldon (Panther).
Ryan Hunter-Reay took ninth for Andretti, alongside Takuma Sato - as KV's Formula 1 convert showed his oval prowess again by breaking into the top 10.
Despite crashing just five laps into practice on his return to the series, Ed Carpenter put the Panther/Vision car 11th, ahead of Andretti's Danica Patrick and Tony Kanaan. Alex Lloyd was another underdog to impress, putting Dale Coyne Racing 14th.
Tomas Scheckter was 17th on his first appearance with Conquest, fellow returnee Ana Beatriz beat her Dreyer & Reinbold team-mate Justin Wilson to 22nd and Davey Hamilton (De Ferran Dragon) qualified 28th in his first outing away from the Indianapolis 500 since his horrific, leg-shattering, crash at Texas nine years ago.
There will be a further 30 minutes of practice at 5pm local time today, with the race taking place under lights on Saturday evening.
Pos Driver Team Speed
1. Ryan Briscoe Penske 216.346mph
2. Dario Franchitti Ganassi 215.593mph
3. Will Power Penske 215.521mph
4. Helio Castroneves Penske 215.475mph
5. Marco Andretti Andretti 215.321mph
6. Graham Rahal Newman/Haas 215.314mph
7. Dan Wheldon Panther 215.099mph
8. Hideki Mutoh Newman/Haas 215.055mph
9. Ryan Hunter-Reay Andretti 214.979mph
10. Takuma Sato KV 214.945mph
11. Ed Carpenter Panther/Vision 214.831mph
12. Danica Patrick Andretti 214.750mph
13. Tony Kanaan Andretti 214.632mph
14. Alex Lloyd Dale Coyne 214.468mph
15. Scott Dixon Ganassi 214.269mph
16. EJ Viso KV 214.210mph
17. Tomas Scheckter Conquest 214.093mph
18. Raphael Matos De Ferran Dragon 213.975mph
19. Alex Tagliani FAZZT 213.910mph
20. Bertrand Baguette Conquest 213.682mph
21. Mario Moraes KV 213.458mph
22. Ana Beatriz Dreyer & Reinbold 213.429mph
23. Justin Wilson Dreyer & Reinbold 213.385mph
24. Vitor Meira Foyt 213.106mph
25. Sarah Fisher Sarah Fisher 213.095mph
26. Milka Duno Dale Coyne 212.777mph
27. Simona de Silvestro HVM 212.660mph
28. Davey Hamilton De Ferran Dragon 212.484mph
29. Jay Howard Sarah Fisher 212.097mph