Charlie Atkins closed in on points leader James McManus as he beat Kieran Kent by 0.597sec in the first race of the weekend.
The early leader slipped to second when Mikey Hardie hit the front a few laps into the race, but just when it looked like he had it in the bag he crashed out on lap six, handing the lead back to Atkins who held it the end.
Christian Smith finished third, some 18secs adrift of Kent as Abbz Thomas enjoyed an astonishing race, fighting through from 30th on the grid to finish fourth, just ahead of Harry Cook in fifth.
HEL Performance British Junior Supersport Championship with Motocourse, Snetterton, Race One:
1. Charlie Atkins (Symcirrus Motorsport)
2. Kieran Kent (D&P Lovell Kent Racing) +0.597s
3. Christian Smith (Smith Twins Racing) +18.692s
4. Abbz Thomas (Symcirrus Motorsport) +24.775s
5. Harry Cook (McAMS Yamaha Junior Team) +24.860s