On his first outing behind the wheel of a Hankook-equipped Škoda Fabia RS Rally2 having switched from driving a Hyundai i20 N Rally2, Vlček took a comfortable victory ahead of Pole Biedrzyński, who continues to rely on Hyundai power for his Master ERC bid.
Tomáš Kurka, driving a Škoda Fabia RS Rally2 for J2X Rally Team, hit back from a crash in testing to complete the top three on his Master ERC debut.
With two rounds remaining, Biedrzyński – who has finished second twice this season – is 13 points ahead of Vlček.
JDS Machinery Rali Ceredigion hosts the penultimate round of the Master ERC season from 5 – 7 September.