Auto GP championship outsider Narain Karthikeyan produced a statement of intent as he set the pace in the opening free-practice session of the weekend at Brno.
The Indian was in command throughout the half-hour session and enjoyed an advantage of in excess of a second for lengthy periods.
His championship-leading Super Nova team-mate Vittorio Ghirelli came closest to Karthikeyan's 1m44.514s time.
Ghirelli's final lap came within 0.353s of the benchmark; the Super Nova pair clear of Zele Racing's returning driver, Tamas Pal Kiss.
Ghinzani driver Robert Visoiu made a promising start to the weekend with fourth spot, ahead of Zele's series debutant, GP2 race winner Josef Kral.
Andrea Roda, who continues to search for his maiden Auto GP podium, completed the top six for Virtuosi Racing.
Ghirelli's closest threat in the title fight Kimiya Sato suffered a troubled practice session owing to exhaust problems, and could only manage 13th spot.
Sato is 11 points behind Ghirelli in the championship with 48 up for grabs at this weekend's finale.
Sergio Campana - the third title protagonist - is 17 behind Ghirelli, and had a subdued session to end up 10th. Karthikeyan is the final championship contender, 21 points off the series lead.
Pos Driver Team Time Gap 1. Narain Karthikeyan Super Nova 1m44.514s 2. Vittorio Ghirelli Super Nova 1m44.867s +0.353s 3. Tamas Pal Kiss Zele 1m45.330s +0.816s 4. Robert Visoiu Ghinzani 1m45.953s +1.439s 5. Josef Kral Zele 1m46.208s +1.694s 6. Andrea Roda Virtuosi 1m46.268s +1.754s 7. Daniel de Jong Manor MP 1m46.745s +2.231s 8. Yoshitaka Kuroda Euronova 1m46.745s +2.231s 9. Kevin Giovesi Ghinzani 1m46.750s +2.236s 10. Sergio Campana Ibiza 1m46.799s +2.285s 11. Roberto La Rocca Comtec/Virtuosi 1m47.141s +2.627s 12. Max Snegirev Virtuosi 1m47.422s +2.908s 13. Kimiya Sato Euronova 1m47.588s +3.074s 14. Meindert van Buuren Manor MP 1m47.707s +3.193s 15. Michela Cerruti MLR 71 1m49.054s +4.540s 16. Francesco Dracone Ibiza 1m50.288s +5.774s 17. Michele La Rosa MLR 71 1m50.701s +6.187s