The blond striker finally ended Co Tyrone's brave resistance as a penalty shoot-out loomed after keeper Patrick Molloy's heroics threatened to keep the Reds at bay.
This was the first time that a County team had reached the final of the competition and a record crowd of 3,602 were clearly backing the home favourites in extremely blustery conditions at the Ballymena Showgrounds.
Demetri Mitchell registered a shot on target after only six seconds but, in truth, the Reds looked a little sluggish at the end of a taxing schedule of five games in as many days. Despite dominating possession, there were few threats on the Northern Irish side's goal - even if Paul McGuinness' youngsters were in total control throughout the first half.
McBurnie, who is with the club on work experience from Bradford City, went close to adding to his goal tally for the tournament but Molloy touched his effort wide following some neat skill by captain Andreas Pereira.
Mitchell rifled a powerful drive straight at Molloy but the Reds struggled to get the other wide man, Joe Riley, into the game and stalemate ensued until the interval. Riley was more involved in the early exchanges of the second half as he headed off target from Mitchell's left-footed centre.
With Mitchell and Pereira, who flashed in a wayward shot, striving to make something happen, United continued to probe. Mitchell streaked out of defence on the break on 51 minutes only to be