Blunham batted first and made 107-6 off their 16 overs, Connor Heaps scoring 36 and Michael Pickard 40. James Howlett took 2 -15 off his 4 overs.
When Potton batted, only Dan Hall got into double figures and they were all out for 49 in 11.4 overs, with Michael Pickard taking four wickets for 19 off 4 overs.
Blunham now play Waresley in their semi. The winners face Biggleswade in the final.