Oli Bayliss destroyed the opposition to storm to his second Feature race win in a row by almost seven seconds.
But while Bayliss celebrated, countryman Jack Mahaffy was left devastated after crashing out from second place on the final lap.
As the 14-lapper got underway, polesitter Luke Stapleford was first into Turn One, but moments later, 2023 champion Ben Currie hit the front, as Mahaffy came through into second.
Bayliss was up to second by the time the pack began Lap Two, quickly moving to the front to lead across the line into Lap Three.
And that was job done at the front, as Bayliss quickly built himself a comfortable lead – but behind, it was far from over.
McAMS Yamaha rider Ben Currie moved back to second on Lap Three but Mahaffy took the spot back on Lap Five – and a lap later, Currie made a mistake and ran onto the grass, dropping back to ninth.
Honda Racing UK’s Jack Kennedy was now third but started to come under pressure from Lee Johnson as the laps wore on, but Johnston was never able to get close enough and in the closing laps he dropped back behind Stapleford.
Following Mahaffy’s crash, Kennedy crossed the line in second position with Stapleford third and Johnston fourth, as Currie was able to pick up a few positions to finish fifth.
Adam Hartgrove was Cup class winner, ahead of James Alderson and Cam Swain.
Quattro Group British Supersport Championship, Feature Race result:
1. Oli Bayliss (Triumph Macadam Factory Racing)
2. Jack Kennedy (Honda Racing UK) +6.975s
3. Luke Stapleford (Scars-Racing Ducati) +7.356s
4. Lee Johnston (SENCAT by Swan Racing) +8.211a
5. Ben Currie (McAMS Yamaha) +16.001s
Championship positions after Round Four:
1. Luke Stapleford 182
2. Ben Currie 146
3. Jack Kennedy 126
4. Dean Harrison 126
5. Oliver Barr 96