There have been many memorable battles down through the years between these sides. This one, at Temple Hill on Saturday, will not rank among the best but Constitution will regard it as one of the sweetest.
For them, it was a real test of character after the disappointment of losing by a point to champions Shannon last week.
Once again, the back row trio of Jerry Murray, Conor Kehelly and Jim Canning made major contributions, but it was half-backs Brian O'Meara and Ronan O'Gara who emerged as the heroes.
O'Meara was instrumental in setting up Constitution's all-important first half try and Murray and O'Gara kicked Young Munster into oblivion.
Yet at half-time the game seemed far from settled. Young Munster out-half Aidan O'Halloran made the most of his opportunities and kicked three first half penalties. O'Gara's penalty and the conversion of Murray's excellent try gave Constitution a narrow cushion.
But if Young Munster supporters anticipated a quick overhaul they were in for an unpleasant surprise. O'Gara kicked brilliantly from the hand and did major damage on the scoreboard.