Gambia international striker Hamza Barry scored the all-important goal for Valletta during the second half.
Valletta join Hibernians on top of the table with four points, followed by Sliema on three and Birkirkara lie at the bottom of the table without any points.
On Tuesday, Sliema Wanderers take on Valletta while on Wednesday, Birkirkara face Hibernians. Both matches will be played at the Centenary Stadium, kick-off at 20:00.
Photo: Copyright © domenic aquilina