Vaclav Pech leads Rally Zlin after he went fastest on Friday night's superspecial through the streets of host city Zlin.
However, with Pech's Mini John Cooper Works S2000 not eligible for Intercontinental Rally Challenge points, his fellow Czech Tomas Kostka tops the main IRC classification.
With the stage run in reverse order, Kostka, a Czech touring car racer and rallysprint competitor of note, was the 86th of 99 drivers to tackle the test, which was momentarily interrupted to enable organisers to deal with an unruly spectator.
Driving a privateer Skoda Fabia Super 2000, the 28-year-old covered the 9.36-kilometre stage in a time of 7m40.0s.
Jan Kopecky was second in a factory Fabia with Ireland's Robert Barrable completing the top three as crews had to contend with damp and slippery conditions following persistent light rain.
Reigning IRC champion Andreas Mikkelsen could only manage the seventh fastest time, 14.4 seconds slower than Kostka, with former title winner Juho Hanninen fifth quickest. Mikkelsen said he was caught out by opting for a dry weather tyre, albeit with cuts, in the belief the rain would subside.
Pavel Valousek, who had been expected to challenge for a podium in his Peugeot 207, hit trouble when he stopped on the stage with a suspected engine fault.
The Zlin stage was a precursor to the opening day of action on the IRC's Czech round, which consists of eight all-asphalt runs. Top seed Juho Hanninen will run first on the road throughout the opening day.
Leading IRC positions after SS1: Pos Driver Team/Car Time/Gap 1. Tomas Kostka Rufa Skoda 7m40.0s 2. Jan Kopecky Skoda + 3.0s 3. Robert Barrable CA1 Skoda + 4.7s 4. Jaroslav Orsak GPD Czech Mitsubishi + 5.2s 5. Juho Hanninen Skoda + 6.4s 6. Roman Kresta Adell Mogul Skoda + 6.9s 7. Andreas Mikkelsen Skoda UK + 14.4s 8. Roman Odlozilik TRT Czech Skoda + 14.9s 9. Andreas Aigner Stohl Subaru + 16.3s 10. Jarkko Nikara Makinen Subaru + 19.6s