Jack Kennedy stole the win after a four-bike scrap in a hectic last lap of Thruxton.
As backmarkers came into play on the final laps, Kennedy was able to sneak ahead at the final corner to beat Bradley Perie over the line by 0.323s.
Behind, Sprint race winner Jack Scott took third after leading a lot of the race on his GP2 machine, as Luke Stapleford – who had also taken his turn leading some of the race – was fourth, just ahead of Jamie Perrin.
Scott’s P2 overall was also P1 in class, with Cameron Fraser the second GP2 machine home in 15th, just one place ahead of third GP2 rider Harry Rowlings.
Quattro Group British Supersport & British GP2 Championship, Thruxton, Feature Race:
1. Jack Kennedy (Mar-Train Yamaha)
2. Bradley Perie (Appleyard Macadam Yamaha) +0.323s
3. Jack Scott (One-Kovara Projects/RS Racing +0.359s
4. Luke Stapleford (Gearlink Kawasaki) +o.448s
5. Jamie Perrin (Yamaha) +6.746s
Championship positions after Round 12:
1. Jack Kennedy 290
2. Bradley Perie 178
3. Harry Truelove 174
4. Luke Stapleford 154