James Reynolds converted a late penalty to secure a thrilling victory for CBC Monkstown, who came back from a seven- point deficit having been a man down early in the second half at Anglesea Road.
St Andrew's cancelled out an early Reynolds penalty through the boot of full-back Andrew Vincent before pushing Sam Gleeson over in the corner while CBC had a man in the sin-bin.
Vincent converted the try to leave CBC playing catch-up, and that's exactly what they did as substitute winger Dean O'Higgins went over in the corner, finishing off a slick piece of play following relentless pressure from the Monkstown pack, to set the stage for Reynolds' heroics.
CBC Monkstown: H Crossan; C Byrne, C Watson, J Reynolds, L Brady ( S Hurley 45); S Power, H Shaw; Luke Hallam, R O'Shea, M Nolan; S Dooley, L Whyte; M Read, T Quinn, Z Sattar.
St Andrew's: A Vincent; D McCaffrey, D Geraghty-Singleton, S Keane L Sigcau; A O'Neill, D James (H Kirk 55); T McVeigh, N Judge, S Gleeson; M Crawford, P Crawford; R Simington, B Crowley, A Sullivan.
Referee: T Colton.