Ben Currie took charge as the Supersport pack hit Oulton Park for the first time this weekend, leading points rival Rhys Irwin by more than a second.
In wet and overcast conditions, the Moto Rapido Ducati Racing rider splashed to a best lap of 1min 46.522s to top the opening timesheets.
Gearlink Bike Performance 15 rider Irwin ended the session second quickest, some 1.369secs adrift of Currie, as Eunan McGlinchey finished third quickest and just 0.051secs behind Irwin.
Joe Talbot emerged best of the rest, the Binch Pro Ducati rider ending the session fourth, just ahead of defending champ, Honda Racing UK’s Jack Kennedy.
After a break at Assen, the Cup action has resumed this weekend, with Ben Tolliday leading the way, Keo Walker second and Stephan Thomas third.
Quattro Group British Supersport Championship, FP1:
1. Ben Currie (Moto Rapido Ducati Racing) 1min 46.522s
2. Rhys Irwin (Gearlink Bike Performance 15) +1.369s
3. Eunan McGlinchey (XMT Racing Triumph) +1.420s
4. Joe Talbot (Binch Pro Ducati) +1.680s
5. Jack Kennedy (Honda Racing UK) +1.682s