Scott Dixon ended the opening day of practice for this weekend's inaugural IndyCar race on the Indianapolis Motor Speedway road course with the fastest time.
The reigning champion claimed the top spot with a fastest lap of 1m10.4654s to edge out Simon Pagenaud by just 0.0191 seconds.
"They've done a great job with the track, one, with the grip level, and two, with the way it's going to race," said Ganassi driver Dixon.
"The car is decent. It's always hard to know what strategies people are on, and it was hard to get a good lap at the end with so much traffic, but hopefully we'll have a good shot at pole tomorrow.
"Maybe the weather conditions will be interesting, too. We'll see."
Will Power recovered from a quiet start to the day for Penske by going third-fastest ahead of Mikhail Aleshin.
Like his Schmidt team-mate Pagenaud, rookie Aleshin had enjoyed a stint as the pacesetter earlier in the session and felt at less of a disadvantage at a track where experience levels are more equal.
"Every race I go to is completely new for me," said the Russian.
"Other than Sonoma and Barber, I haven't tested anywhere."
Josef Newgarden and Jack Hawksworth both had their afternoons shortened as punishment for being late to the mandatory weigh-in after the morning session; the pair being forced to park six and three minutes early respectively.
It was an encouraging start for the two drivers making cameo appearances this weekend, with both Martin Plowman (driving a second AJ Foyt car) and Franck Montagny (in a fifth Andretti entry) lapping within 0.7s of Dixon's time, although the tight nature of the field meant that this left both outside the top 20.
The opening day's running was forecast to be the warmest part of the race weekend, with rain predicted for Friday's qualifying session ahead of a dry but cooler race on Saturday.
Pos Driver Team/Engine Time Gap
1. Scott Dixon Ganassi/Chevy 1m10.4654s
2. Simon Pagenaud Schmidt/Honda 1m10.4845s +0.0191s
3. Will Power Penske/Chevy 1m10.5672s +0.1018s
4. Mikhail Aleshin Schmidt/Honda 1m10.6681s +0.2027s
5. James Hinchcliffe Andretti/Honda 1m10.7558s +0.2904s
6. Graham Rahal Rahal/Honda 1m10.7893s +0.3239s
7. Ryan Hunter-Reay Andretti/Honda 1m10.7937s +0.3283s
8. Justin Wilson Coyne/Honda 1m10.7980s +0.3326s
9. Marco Andretti Andretti/Honda 1m10.8113s +0.3459s
10. Tony Kanaan Ganassi/Chevy 1m10.8175s +0.3521s
11. Charlie Kimball Ganassi/Chevy 1m10.8180s +0.3526s
12. Sebastian Bourdais KV/Chevy 1m10.8194s +0.3540s
13. Juan Pablo Montoya Penske/Chevy 1m10.8707s +0.4053s
14. Helio Castroneves Penske/Chevy 1m10.9026s +0.4372s
15. Jack Hawksworth Herta/Honda 1m10.9485s +0.4831s
16. Carlos Munoz Andretti/Honda 1m11.0120s +0.5466s
17. Ryan Briscoe Ganassi/Chevy 1m11.0167s +0.5513s
18. Josef Newgarden Fisher/Honda 1m11.0230s +0.5576s
19. Takuma Sato Foyt/Honda 1m11.0400s +0.5746s
20. Sebastian Saavedra KV/Chevy 1m11.1683s +0.7029s
21. Martin Plowman Foyt/Honda 1m11.1760s +0.7106s
22. Franck Montagny Andretti/Honda 1m11.2437s +0.7783s
23. Oriol Servia Rahal/Honda 1m11.3928s +0.9274s
24. Carlos Huertas Coyne/Honda 1m11.3987s +0.9333s
25. Mike Conway Carpenter/Chevy 1m11.5687s +1.1033s