RHYS Irwin topped the opening session timesheets at a wet Knockhill with a lap of 55.362secs, beating Sam Munro and Luke Stapleford.
As many riders opted not to go out in the wet session, GP2 runner Korie McGreevy ended fourth, just ahead of Bradley Perie.
Quattro Group British Supersport Championship, Knockhill, FP1: Irwin on top in rain-hit session
1. Rhys Irwin (Astro JR Triumph)
2. Sam Munro (Munro Racing) +0.363secs
3. Luke Stapleford (Gearlink Kawasaki) +0.840secs
4. Korie McGreevy (Chassis Factory – Go Racing Developments SGR) +0.866secs
5. Bradley Perie (Appleyard Macadam Racing) +1.165secs