Charlie Atkins took the opening Junior Supersport win by a mere 0.086secs over Kieran Kent.
In a close run race, Mikey Hardie crossed the line third a further half second behind, with Joe Ellis fourth and Jack Roach fifth.
HEL Performance British Junior Supersport Championship with Motorcourse, Oulton Park, Race One:
1. Charlie Atkins (Symcirrus Motorsport)
2. Kieran Kent (D&P Lovell Kent Racing) +0.086s
3. Mikey Hardie (Completely Motorbikes/Affinity) +0.614s
4. Joe Ellis (JPR) +1.733s
5. Jack Roach (Completely Motorbikes/Affinity) +1.950s