Dan Linfoot was back on the box after storming to the opening Superstock win at Knockhill ahead of polesitter Richard Kerr.
After a strong race, Linfoot eventually crossed the line 3.756secs ahead of Kerr, as Alex Olsen finished third, a further two seconds back.
Fourth place went to local hero Lewis Rollo as Alastair Seeley took fifth.
Pirelli National Superstock Championship with Santander Consumer Finance race one:
1. Dan Linfoot (Optimum Bikes Racing Ltd)
2. Richard Kerr (AMD Motorsport) +3.756s
3. Alex Olsen (Cumins by Team IWR Honda) +6.198s
4. Lewis Rollo (IN Competition/Aprilia) +7.385s
5. Alastair Seeley (SYNETIQ BMW Motorrad) +7.711s