United edged an entertaining first half thanks to Steve Callinan - good work down the left by Phil Mason gave the in-form striker the easiest of chances from close range. However, Wealdstone did come close to scoring, forcing Scott Honeyball to make a goal-line clearance.
Any chance the home side may have had disappeared on the hour, when the outstanding Roni Joe took on several home defenders before firing in from an acute angle.
The introduction of another ex-Duck Mickey Swaysland briefly threatened to spoil the party when he scored with an unstoppable shot shortly after he joined the game as substitute.
But Roni restored the Ducks' two-goal advantage almost immediately with his second of the evening - a near carbon copy of his first.