All-rounder Kevin Sinclair picked up 7 wickets to help Berbice defend a below-par 132.
Demerara could only muster 105 as they were all out inside 26 overs.
Demerara did well to restrict Berbice to a paltry 132 all out in 32.4 overs. Romario Shepherd top-scored with 26 off 42 balls which included 4 fours.
Steven Sankar led the way for Demerara with figures of 3-22 while Qumar Torrington took 2-22 and Sherfane Rutherford 2-18.
Sinclair then single-handedly bowled his team to victory, snagging 7-15 from 9.5 overs.
Looknauth top-scored for Demerara with his knock of 36 while Matthew Nandu contributed 21.
The second match of Round 1 continues Sunday with the GCB Select XI taking on Essequibo from 09:00h at the Georgetown Cricket Club Ground.
Scores:
Berbice 132 All Out (32.4 overs)
Shepherd 26, Sankar 3-22, Rutherford 2-18, Torrington 2-22
Demerara 105 All Out (25.5 overs)
Looknauth 36, Nandu 21, K Sinclair 7-15