Tony Kanaan was quickest in final practice ahead of qualifying for the IndyCar title decider at Las Vegas.
The Brazilian KV Racing Technology driver edged out Oriol Servia (Newman/Haas) by 0.0246 seconds.
Andretti Autosport's Ryan Hunter-Reay was third, ahead of Ganassi driver Scott Dixon, Kanaan's team-mate EJ Viso.
Several unexpected names popped up in the top 10, led by HVM's Simona de Silvestro in sixth. Vitor Meira was another star underdog in seventh for AJ Foyt, while series returnee Tomas Scheckter put Sarah Fisher Racing's additional entry into eighth place.
The majority of the top 10 came from the second group of the split session. Hunter-Reay had led group one, ahead of his team-mate Mike Conway and Sam Schmidt driver Alex Tagliani, who ended up ninth and 10th on combined times.
Title contenders Will Power (Penske) and Dario Franchitti (Ganassi) had low-key sessions and were 12th and 15th.
The only incident of the session happened within minutes of the start of group one, as Dale Coyne Racing's James Jakes had a violent, fiery impact with the Turn 2 wall after a breakage in his car's left rear suspension. Jakes jumped out of the car immediately and escaped with minor burns. He will not be able to participate in qualifying, which starts only 45 minutes after the end of practice.
Pos Driver Team Time Gap 1. Tony Kanaan KV 24.7926s 2. Oriol Servia Newman/Haas 24.8172s + 0.0246s 3. Ryan Hunter-Reay Andretti 24.8218s + 0.0292s 4. Scott Dixon Ganassi 24.8433s + 0.0507s 5. EJ Viso KV 24.9050s + 0.1124s 6. Simona de Silvestro HVM 24.9060s + 0.1134s 7. Vitor Meira AJ Foyt 24.9065s + 0.1139s 8. Tomas Scheckter Sarah Fisher 24.9366s + 0.1440s 9. Mike Conway Andretti 24.9561s + 0.1635s 10. Alex Tagliani Bryan Herta 24.9582s + 0.1656s 11. Ryan Briscoe Penske 24.9609s + 0.1683s 12. Will Power Penske 24.9645s + 0.1719s 13. Graham Rahal Ganassi 24.9689s + 0.1763s 14. Helio Castroneves Penske 24.9738s + 0.1812s 15. Dario Franchitti Ganassi 24.9839s + 0.1913s 16. Ed Carpenter Sarah Fisher 24.9931s + 0.2005s 17. James Hinchcliffe Newman/Haas 25.0103s + 0.2177s 18. Townsend Bell Dreyer & Reinbold 25.0112s + 0.2186s 19. Marco Andretti Andretti 25.0115s + 0.2189s 20. Danica Patrick Andretti 25.0602s + 0.2676s 21. Jay Howard Rahal Letterman Lanigan 25.0796s + 0.2870s 22. Buddy Rice Panther 25.0816s + 0.2890s 23. Alex Lloyd Dale Coyne 25.0848s + 0.2922s 24. Sebastian Saavedra Conquest 25.0855s + 0.2929s 25. JR Hildebrand Panther 25.0931s + 0.3005s 26. Ana Beatriz Dreyer & Reinbold 25.0985s + 0.3059s 27. Charlie Kimball Ganassi 25.1128s + 0.3202s 28. Takuma Sato KV 25.1166s + 0.3240s 29. Pippa Mann Rahal Letterman Lanigan 25.1319s + 0.3393s 30. Paul Tracy Dragon 25.1346s + 0.3420s 31. Wade Cunningham AFS/Sam Schmidt 25.1633s + 0.3707s 32. Dan Wheldon Sam Schmidt 25.2320s + 0.4394s 33. Davey Hamilton Dreyer & Reinbold 25.2928s + 0.5002s 34. James Jakes Dale Coyne 25.3158s + 0.5232s