Evan Belford converted pole to the win as he beat Carter Brown by 0.175secs after a last lap battle.
But Brown, who finished second, looks on course to secure runner-up spot in the championship after Rhys Stephenson, who had been sitting third in the points, crashed out on lap 12.
Third was Harley McCabe, just ahead of Lucas Brown with Harrison Crosby fifth.
Honda British Talent Cup, Donington Park, Race One:
1. Evan Belford (City Lifting by RS Racing)
2. Carter Brown (MLav VisionTrack Academy) +0.175s
3. Harley McCabe (MLav VisionTrack Academy) +8.755s
4. Lucas Brown (SP125/Amphibian Scaffolding) +14.928s
5. Harrison Crosby (Banks Racing) +20.736s