Oli Bayliss saved his best until last after a penultimate lap move to beat Luke Stapleford by 2.242sec and banked a new lap record.
The Australian had started from pole and got a strong start to hit the front, closely followed by Stapleford. Fellow Australian, Jack Mahaffy, also got away well, launching himself up to third from the second row.
It took Stapleford less than a lap to get ahead with a move into Lodge Corner but Bayliss stuck close behind, making a move on the third lap, as Stapleford came straight back and re-took the lead.
Bayliss hit the front again on Lap Six and this time it was Stapleford’s turn to sit on his rear when as the leading duo began to leave the rest of the pack behind.
Mahaffy was still running third and somehow holding off the charging Honda Racing UK pairing of Dean Harrison and Jack Kennedy. Kennedy found a way past his team-mate and then on Lap Seven passed Mahaffy.
Harrison also found his way past the Australian as did Harry Truelove in the closing laps while up front, Stapleford and Bayliss were still locked in their own battle.
Bayliss led into the penultimate lap but Stapleford got past into Island, only for his rival to go straight back underneath at Hizzy’s.
And there was no chance of the battle continuing as Bayliss then pulled the pin and left Stapleford behind, crossing the line at the end of Lap 10 2.242secs clear of Stapleford with a new lap record.
Kennedy emerged third with Harrison fourth as Truelove rounded out the top five.
Cam Swain continued to lead in the Cup class, finishing p14 overall and one place ahead of Keo Walker as Ben Tolliday was third.
Quattro Group British Supersport Championship, Sprint result:
1. Oli Bayliss (Triumph Macadam Factory Racing)
2. Luke Stapleford (Scars-Racing Ducati) +2.242s
3. Jack Kennedy (Honda Racing UK) +6.257s
4. Dean Harrison (Honda Racing UK) +6.829s
5. Harry Truelove (McAMS Yamaha) +8.428s