Can Öncü crossed the line first at the end of a breathtaking 18-lap Feature race after a five rider scrap which raged from lights to flag.
Öncü beat fellow World Supersport star Oli Bayliss by 0.260secs at the end of 18 hard-fought laps – as Luke Stapleford played it cool to take third and boost his points lead.
From pole position, Bayliss launched off the start and into the lead but both Josh Whatley and Harry Truelove scorched past and began their own scrap for the lead, Truelove leading over the line at the end of the first two laps.
Öncü – deputising for the injured Ben Currie on the McAMS Yamaha – had to fight back from ninth on the grid but made swift progress and was up with the leading group of six by the end of Lap Five as Jack Kennedy now hit the front.
By now the lead was changing constantly each lap, with Öncü getting ahead on Lap Seven. However, it was still impossible to call as Öncü, Kennedy, Bayliss and Whatley continued to trade places.
Stapleford had been running at the back of the leading pack and with five laps to go decided to make his presence known as he threw himself into the mix as the lead kept changing.
On Lap 15, with Öncü ahead, the Safety Car came out following a crash further down the pack and when it went in at the end of Lap 16, Öncü backed the pack up well to get a great restart.
Kennedy and Bayliss were running second and third with Stapleford fourth and as they scrapped with each other, Öncü almost had a bit of breathing space ahead.
It all came down to the final part of the last lap. Öncü had by now given himself the smallest of leads and Stapleford was now ahead of Kennedy. As they all charged into the chicane, Bayliss almost looked like he was about to lose it but he managed to keep momentum as behind, Stapleford was able to hold off Kennedy.
Öncü made it over the line 0.260secs clear of Bayliss as Stapleford was third, 0.108secs ahead of Kennedy, leaving Whatley to round out the top five.
Cam Swain took the win in the Cup class, just ahead of James Alderson with third place going the way of Stephen Thomas.
Quattro Group British Supersport Championship, Feature race result:
1. Can Öncü (McAMS Yamaha)
2. Oli Bayliss (Triumph Macadam Factory Racing) +0.260s
3. Luke Stapleford (Scars-Racing Ducati) +0.506s
4. Jack Kennedy (Honda Racing UK) +0.614s
5. Josh Whatley (XMT Racing) +0.752s
Championship positions after Round Seven:
1. Luke Stapleford 301
2. Jack Kennedy 246
3. Oli Bayliss 234
4. Dean Harrison 196
5. Ben Currie 184