A lap of 2min 8.201secs was enough to give Pesek a promising start to the weekend's proceedings, with championship leader Gabor Talmacsi coming within a tenth of a second of his rival's time.
The provisional front row consists of Pesek, Talmacsi, Mattia Pasini and Hector Faubel; all four race winners in 2007 but only Pesek has failed to take pole position.
Sandro Cortese, Tomoyoshi Koyama, Sergio Gadea and Randy Krummenacher also picked up the pace for a provisional start from the second line of attack, with the latter having played a part in MotoGP's Vienna visit that brought the main street to a standstill on Wednesday.
First qualifying – Brno:1. Pesek (Derbi)
2. Talmacsi (Aprilia) +0.082secs
3. Pasini (Aprilia) +0.178secs
4. Faubel (Aprilia) +0.224secs
5. Cortese (Aprilia) +0.457secs
6. Koyama (KTM) +0.793secs
7. Gadea (Aprilia) +0.818secs
8. Krummenacher (KTM) +1.121secs
9. Espargaro (Aprilia) +1.294secs
10. Corsi (Aprilia) +1.448secs
14. Smith (Honda) +2.090secs
29. Webb (Honda) +4.099secs