Richard Cooper saw off his big championship rival Thomas Strudwick to take the first Heat win at Donington Park.
Although the pair spent the opening laps swapping the lead between them, Cooper managed to eke out a small gap by the penultimate lap which was enough to keep Strudwick at bay as Cooper took the win by 1.4 secs.
Christian Smith was third as James Nagy took fourth while Harley Prebble just inched ahead of James Kelly on the final lap to secure fifth.
ABK Beer 0% BMW Motorrad F900 R Cup, Heat One result:
1. Richard Cooper (FHO Racing BMW Motorrad)
2. Thomas Strudwick (Art of Racing) +1.400s
3. Christian Smith (SCH Motoprep/Smith Twins Racing) +4.582s
4. James Nagy (Nagy Racing) +4.847s
5. Harley Prebble (Harley Prebble Racing) +8.840s