A last-gasp effort from Will Power was rewarded with the bragging rights after the second IndyCar practice session at Mid-Ohio.
Penske driver Power registered a 1m05.4332s on his final lap to take the top spot from Ganassi's Scott Dixon, who had also done his best time right at the end but finished up 0.01 second short.
"We got a good time in at the end. A few mistakes during the session but we're narrowing it down," Power said. "I'd love nothing more than to get on the pole here and have a chance to win a race. But good so far, and we'll keep working hard."
Until the last couple of minutes the benchmark had been Ryan Hunter-Reay, whose time was still good enough for third-fastest ahead of Dario Franchitti, while series debutant Luca Filippi did a great job to finish up fifth for Bryan Herta Autosport.
Fellow first-timer James Davison's day ended with the Australian in 19th, while Dale Coyne Racing team-mate Justin Wilson's afternoon was derailed by an engine problem that restricted the Englishman to just two flying laps.
The afternoon was interrupted by two brief stoppages, the first coming when James Hinchcliffe went off at Turn 11 and the second when Tony Kanaan hit the tires at Turn 12, although both were able to rejoin the session later.
Pos Driver Team/Car Time Gap
1. Will Power Penske/Chevy 1m05.4332s
2. Scott Dixon Ganassi/Honda 1m05.4469s +0.0137s
3. Ryan Hunter-Reay Andretti/Chevy 1m05.5018s +0.0686s
4. Dario Franchitti Ganassi/Honda 1m05.7019s +0.2687s
5. Luca Filippi Herta/Honda 1m05.7364s +0.3032s
6. Charlie Kimball Ganassi/Honda 1m05.7692s +0.3360s
7. Marco Andretti Andretti/Chevy 1m05.7796s +0.3464s
8. James Hinchcliffe Andretti/Chevy 1m05.7939s +0.3607s
9. Simon Pagenaud Schmidt/Honda 1m05.8653s +0.4321s
10. Simoa de Silvestro KV/Chevy 1m05.8714s +0.4382s
11. Tony Kanaan KV/Chevy 1m05.9295s +0.4963s
12. Helio Castroneves Penske/Chevy 1m05.9422s +0.5090s
13. Sebastien Bourdais Dragon/Chevy 1m06.0223s +0.5891s
14. Josef Newgarden Fisher/Honda 1m06.0886s +0.6554s
15. Tristan Vautier Schmidt/Honda 1m06.0979s +0.6647s
16. EJ Viso Andretti/Chevy 1m06.1083s +0.6751s
17. Oriol Servia Panther/Chevy 1m06.1330s +0.6998s
18. Graham Rahal Rahal/Honda 1m06.2438s +0.8106s
19. James Davison Coyne/Honda 1m06.4680s +1.0348s
20. James Jakes Rahal/Honda 1m06.5809s +1.1477s
21. Sebastian Saavedra Dragon/Chevy 1m06.6246s +1.1914s
22. Takuma Sato Foyt/Honda 1m07.3160s +1.8828s
23. Ed Carpenter Carpenter/Chevy 1m07.7526s +2.3194s
24. Justin Wilson Coyne/Honda 1m10.3923s +4.9591s