Ed Carpenter topped the final practice session ahead of Saturday's IndyCar season finale at Fontana.
Carpenter set his 215.768mph lap just after a late restart to move ahead of Helio Castroneves, whose 215.108mph effort had been the one to beat for most of the Friday evening session.
Scott Dixon, Tony Kanaan and Josef Newgarden rounded out the top five.
It was a subdued evening for both of the championship contenders, with Ryan Hunter-Reay's 209.360mph best leaving him 21st, and Will Power a further two places behind with a fastest lap of 208.243mph.
Wade Cunningham prompted a late full-course yellow when he lost the rear of his AJ Foyt entry and brushed the wall at Turn 2.
The New Zealander, who was drafted in at the 11th hour to replace Mike Conway, was taken to the infield medical centre for checks and has been cleared to drive on Saturday.
Cunningham's was the second caution of the session, with an earlier, longer spell under yellows having been prompted by a track inspection.
Pos Driver Team/Car Time Gap
1. Ed Carpenter Carpenter Dallara-Chevy 33.3691s
2. Helio Castroneves Penske Dallara-Chevy 33.4715s + 0.1024s
3. Scott Dixon Ganassi Dallara-Honda 33.4801s + 0.1110s
4. Tony Kanaan KV Dallara-Chevy 33.6348s + 0.2657s
5. Josef Newgarden Fisher Dallara-Honda 33.6723s + 0.3032s
6. Ryan Briscoe Penske Dallara-Chevy 33.7275s + 0.3584s
7. JR Hildebrand Panther Dallara-Chevy 33.7502s + 0.3811s
8. Justin Wilson Coyne Dallara-Honda 33.7875s + 0.4184s
9. Graham Rahal Ganassi Dallara-Honda 33.9379s + 0.5688s
10. Oriol Servia Panther/DRR Dallara-Chevy 33.9641s + 0.5950s
11. Dario Franchitti Ganassi Dallara-Honda 33.9904s + 0.6213s
12. Rubens Barrichello KV Dallara-Chevy 34.1008s + 0.7317s
13. Marco Andretti Andretti Dallara-Chevy 34.1227s + 0.7536s
14. Takuma Sato Rahal Dallara-Honda 34.1330s + 0.7639s
15. James Jakes Coyne Dallara-Honda 34.1514s + 0.7823s
16. Katherine Legge Dragon Dallara-Chevy 34.1601s + 0.7910s
17. James Hinchcliffe Andretti Dallara-Chevy 34.2000s + 0.8309s
18. Simon Pagenaud Schmidt Dallara-Honda 34.2912s + 0.9221s
19. Alex Tagliani Herta Dallara-Honda 34.3049s + 0.9358s
20. Charlie Kimball Ganassi Dallara-Honda 34.3469s + 0.9778s
21. Ryan Hunter-Reay Andretti Dallara-Chevy 34.3905s + 1.0214s
22. Sebastian Saavedra AFS/Andretti Dallara-Chevy 34.3905s + 1.0214s
23. Will Power Penske Dallara-Chevy 34.5750s + 1.2059s
24. EJ Viso KV Dallara-Chevy 34.6401s + 1.2710s
25. Wade Cunningham Foyt Dallara-Honda 35.0168s + 1.6477s
26. Simona de Silvestro HVM Dallara-Lotus 37.0575s + 3.6884s