With the victory, Sundowns move back into second spot on the log with 51 points, three ahead of third-placed Orlando Pirates on 48.
For Stars, meanwhile, the loss on their home turf was ill-timed as they remain 13th on the log with 31 points and two games left in their season.
Tlou Segolela weaved his way into the Sundowns box in the fourth minute, before reeling off a shot which was deflected away for a corner.