Glenrothes got off to the perfect start when, after only two minutes on the clock, a Dall corner kick was met by Euan Belford, whose header gave the keeper no chance.
Athletic were creating chances, and they doubled their lead midway through the half when Dall finished well inside the box.
A deserved half-time lead, and on the face of play, should have been more going in at the interval.
The second half turned into a scrappy affair with very little in terms of clear cut chances either way. With just under 15 minutes left, Abernethy were thrown a lifeline when they scored from the penalty spot after a foul inside the box.
With the game opening up, Athletic ensured their place in the next round when Dall got his second from close range in the dying minutes. Glenrothes will meet Thornton Hibs’ conquerors Bayview in the next round.