It was a poor start for the Ellon side as they conceded a penalty inside the first couple of minutes after Thomson was adjudged to have fouled one of the Deveronside attackers, reacting to a shot from a distance that deflected off the hosts’ crossbar.
Kirton was beaten from 12 yards despite going the right way which meant Ellon were 1-0 down.
United, however, grew in confidence in the game and Massie went close as his header was pushed behind for a corner from a Tait cross.
Irvine was next to go close, heading just over from another tantalising Tait ball in.
Bain then had the ball in the net only for the flag to spoil his party as it was raised for offside.
Irvine and Coutts were both denied by interventions; the latter denied by a marvellous point blank save from the visiting keeper.
However, just before half-time, Ellon got their reward as they were awarded a penalty when Bain was bundled over in the box from a long Gibbon free kick.
Tait stepped up and scored from 12 yards to bring the hosts level.
The second half began well for Ellon with Tait going close with a chipped effort wide and Bain also flashing a header wide of the far post.
Irvine was next to be denied, seeing his header from a Tait corner go just past.
McDonald, who came off the bench for Bain, also saw an effort go just off target.
However, despite Ellon dominating for large parts of the second half, it was the visitors who re-established their advantage, scoring a fine goal on the break, leaving Kirton with no chance.
The impressive Tait was then replaced by Sim and Smith also came on late on for the industrious Shand as Ellon pushed for an equaliser to send them through courtesy of goal difference.
It seemed like it wasn’t going to be Ellon’s day as Irvine, McDonald and Sim were all off target before Kirton made a fabulous stop at the other end to prevent the visitors from adding to their lead.
However, right at the end, Ellon got their rewards and, in keeping with the game, it came from yet another set play.
The corner was delivered into the box towards Gibbon. His header was blocked on the goal line but at the far stick it was left to Burr to come stealing in and nod the rebound high into the net to draw United level and cue absolute pandemonium inside The Meadows.
It was no less than Ellon deserved and there was barely any time for the restart to take place when the referee blew for full time as, with a superior goal difference, Ellon progressed to the next round.