A fourth wicket stand of 130 between Tim Tector and Rhys Armah Kwantreng led YMCA to the league title as they beat Rush by five wickets in the play-off decider.
Chasing 173, YMCA were in early trouble at 23 for 3, but Tector played superbly making 80 before retiring, and was excellent supported by Kwantreng, who hit 52.
Diarmuid Burke (3-19) and Cian Rock (1-37) were the successful bowlers for Rush.
The Rush total of 173 for 7 was based around an excellent half century for Jack McGee (55), while Andrew Doheny (27), Nathan McGuire (21), and Daniel Thorne (18) all chipped in.
Ben Brownlee, Jack Davy, and Wilhelm de Klerk all bowled well.
Rush have the consolation of still being involved in the All-Ireland U15 finals where they will play either Eglinton or St Johnston who are due to play September 2nd, meaning the final will likely be played Sunday 9th or 16th of September.
U15 LEAGUE FINAL
At Claremont Road, YMCA beat Rush by 5 wickets
Rush 173-7 (30 overs; Jack McGee 55, Andrew Doheny 27, Nathan McGuire 21, Daniel Thorne 18, Rhys Armah Kwantreng 1-24, Ben Brownlee 1-27, Jack Davy 1-28, Wilhelm de Klerk 1-30)
YMCA 174-5 (27.2 overs; Tim Tector 80 retd, Rhys Armah Kwantreng 52, Diarmuid Burke 3-19. Cian Rock 1-37)