A gripping game at Dooradoyle as Ardscoil grounded out a dramatic win to qualify for the semi finals of the SEAT Munster Schools Senior Cup.
Sloppy defending allowed Christians wing forward Dan Walsh in for a try after seven minutes and Jason Higgins converted.
Higgins added a penalty shortly after but slowly Ardscoil worked their way into the game despite playing into the strong wind. Full back Stephen Fitzgerald scored a super try to open the Limerick side's account.
Higgins made it 13-5 with a penalty before a try by Ardscoil winger Liam Brock closed the gap to three points, six minutes before the break.
Christians upped the ante after the break and Walsh was in for Christians second try after blocking down a clearance by Jack O'Donnell and Higgins converted to make it 20-10.
Mid way through the half Brion Moriarty scored an Ardscoil try and David O'Mahony converted.
O'Mahony was Ardscoil's hero as he broke through the Christians defence to touch down
with six minutes remaining.
The Cork side rallied in the closing stages but the Ardscoil defence held firm.
Ard Scoil Ris: Stephen Fitzgerald; Brion Moriarty, Paul McNamara, Jack O'Donnell, Liam Brock; David O'Mahony, Diarmuid Scannell; Jack O'Halloran, Shane Fenton, Tommy Walsh; Darragh Ryan, Patrick Staff; Joe Cannon, Jerry McCabe, Kelvin Brown.
Replacements: Ty Chan, Pierce Lyons, Killian Bracken, Barra O'Byrne, Hugh Bourke, Joey Walshe, Lloyd White.
CBC: Cormac O'Mahoney; Thomas Tracey, Michael Clune, Shane McAuliffe, Ben O'Callaghan; Jamie Murphy, Jason Higgins; Liam O'Connor, Vincent O'Brien, Greg Roche; Glen Stokes, Cian Barry; Evan Mintern, Dan Walsh, Shane O'Hanlon.
Replacements: Eoin Scully, Colm Fitzgerald, Conor Leahy, Lee McSherry, David Parfrey, Richie Cassidy, Oisin McSweeney, David Grufferty.
Referee: Ollie Hodges (MAR).
SEAT Munster Senior Cup Results 26.02.14
Crescent College Comprehensive 21, PBC 21
St. Munchin's College 23, Rockwell College 10
Ardscoil Rís 22, CBC 20