Terenure College emerged as the Leinster Schools Section C Senior Cup champions after a titanic struggle against St Mary's at Lansdowne Road.
It was always going to be a low-scoring game as both sides came to the final with impressive defensive records.
Indeed, the only score of the game came after 50 minutes when Terenure full-back Robert McCarthy countered effectively and out-half Conor Gildea was almost through on a break.
St Mary's gave away a penalty in their haste and centre Gary Byrne curled the penalty just inside the left hand upright for a famous victory.