Alastair Seeley has reduced the gap on British Supersport leader Billy McConnell to 38 points after winning Saturday's sprint race at Silverstone.
The Carrickfergus rider lies third in the standings going into Sunday's feature race in the penultimate round of the series.
Taylor Mackenzie was over nine seconds behind with James Rispoli in third.
Fellow Carrick man Glenn Irwin battled for the lead with Seeley but was forced to retire on lap five.
Irwin is fourth in the championship but 95 points behind McConnell and out of title contention.
"We pulled it out of the bag in qualifying to get on the front row and I knew once the race started that I was comfortable running my own pace in the tricky conditions," said Seeley.
"I knew I would have to deal with Irwin and he's riding well, but the idea was to get away on my own as I knew I would be comfortable at the front.
"I could see his shadow and he made a few lunges, but once I was on my own I just kept my focus and that's win number seven this season."