There were three minutes left on the clock when scrum-half Sean Fahey burst over on the blindside to help Sandford Park to squeeze past De La Salle Churchtown 29-24 in the first round at Ballycorus yesterday.
This was a cracking contest, Sandford edging it 5-3 on the try count with a brace from flanker Kris Assaff-Kirk and further touchdowns from wing Matthew Tector and James Orr.
DLS kept in the hunt with a pair of intercept tries by their captain Scott Finlay and the various skills of scrum-half Kevin Burke, who notched the other try and nine points from the boot.
St Andrew's had to recover from the early sucker-punch of a try by Skerries Community College captain Niall Collins to record a 19-5 win at Westmanstown.
Thereafter, the Booterstown boys turned up the pressure, and the territorial advantage told with tries from No 8 Nathan Felton, scrum-half Daniel Joyce and flanker Killian McCarthy, their captain.
Newpark Comprehensive out-half Fergal Howley held his nerve to kick the winning penalty three minutes from time in a superb encounter against Gorey Community School (18-17) at Greystones RFC.
This really was a proper Cup match in that the lead changed hands five times. Centre Ronan Sherlock and flanker Aaron Campbell pierced the Gorey defence, while the losers struck back with tries from forwards James Mulligan, Eddie Earle and Jordan Ahearne.
Wing wizard Phil O'Neill was the hero with four tries in Newbridge College's 55-3 eclipse of Wilson's Hospital at North Kildare RFC.
It was one-way traffic, O'Neill striking twice in each half together with efforts from right wing Ivan Briody, centre Charlie Ryan, out-half Mark Sutton, lock Billy Scully and replacement Billy Delaney, while Wilson's were restricted to a penalty by Reuben Pepper-Hobbs.
Captain Stephen Alexander showed the way with a pair of tries in High School's facile 40-0 defeat of a game St Conleth's College at Sydney Parade.