Jacob Stephenson stole pole from Lewis Jones in the closing minutes of qualifying, with a lap of 1min 44.648s to seal the deal by 0.091s.
Jones, who had been quickest in free practice, looked on course to dominate but crashed out and was unable to better his time, as Joe Ellis finished third on exactly the same time as Jones, with Finn Smart-Weeden fourth and Lennon Docherty fifth.
HEL Performance British Junior Supersport Championship with Motocourse, Qualifying:
1. Jacob Stephenson (Kevin Stephenson) 1min 44.648s
2. Lewis Jones (Symcirrus Motorsport) +0.091s
3. Joe Ellis (JPR) +0.091s
4. Finn Smart-Weeden (Wrapped Racing by Club 74) +0.216s
5. Lennon Docherty (Symcirrus Motorsport) +0.220s