Championship leader Nikki Coates pipped Barry Burrell to the best time in FP1 as he clocked a 1min 21.653sec on his final lap.
The LDC BMW by FPF Racing rider saved his best until last as he stuck in his hot lap in the closing moments to go 0.807s clear of Burrell, who had led most of the session.
Christian Smith was third quickest with twin brother Kieran just behind him, as James Bull rounded out the top five.
ROKiT Off BMW F 900 R Cup, FP1:
1. Nikki Coates (LDC BMW by FPF Racing) 1min 21.653s
2. Barry Burrell (Halliwell Jones Motorrad) +0.807s
3. Christian Smith (SCH Motoprep/Bathams Racing) +1.494s
4. Kieran Smith (Bowker Motorrad/Bathams Racing) +1.737s
5. James Bull (James Bull Racing) +2.417s