Down's senior side was in a great position to win this match but contrived to throw the opportunity away with some poor finishing.
The locals had clawed their way back into the game at 2-2 when they created three gilt-edged chances which would have taken the game away from their opponents.
Sadly, the forwards missed the target, allowing Armagh to regroup and score three more goals to leave the final scoreline a little flattering in their favour.
Down took the lead in the 16th minute through Jordan Aidey who finished off a move at the back post, with the goal created via Aaron Ferris and Sinclair White.
Armagh made it 1-1 from the penalty spot, with the stroke awarded after a goal-bound shot struck Philip Brown on the foot and umpire Joe Robson, Ñ who was superb throughout Ñ rightly pointed to the spot.
Armagh got their noses in front shortly before the interval from a short corner, after a tackle by James Erskine on a forward was penalised. From the resultant set-piece, a strong shot was sandwiched between 'keeper Jeremy McCready and sweeper Chris Taylor.
Down played their best hockey of the day within minutes of the restart with White hammering home a trademark short corner strike that gave the 'keeper no chance.
With their tails up, Down should have gone in and scored at least three more goals. Mark Elliott was through on goal with just the 'keeper to beat but managed to dink the ball wide of a gaping goal, while Ferris then fluffed his lines when it looked as though he would score.
Gavin Ringland then had a chance to make it 3-2 but he also couldn't hit the target, allowing Armagh to launch a swift counter-attack which led to their third goal.
The home side then moved up a gear as Down tried to push forward for an equaliser, with Armagh scoring two more goals before the end.
This Friday night Down have a chance to get back to winning ways when they face derby rivals Ballynahinch at St. Colman's High and Sixth Form College. The game starts at 8.15pm.