Leinster launched their title defence with an emphatic seven-wicket win against the Southern XI at Terenure.
YMCA's Jamie Forbes took four wickets as the Southern XI struggled to 92 all out - extras being their top contributor with 35.
Ciaran Sheridan battled bravely for his 26, with John Devane (13) the only other player to reach double figures.
The Rush duo of Daniel Thorne and Diarmuid Burke each picked up two wickets in an impressive display by the bowling unit. Hugo Neville claimed 1 for 9, while skipper Tim Tector got a run out.
Rush team-mates Nathan McGuire (28) and Jack McGee (17) ensured there would be little fuss in chasing down their modest total as they both hit three boundaries in an opening stand of 49.
Matthew Lynch made 12, while the seven-wicket win was ensured by Craig Mackay (15*) and Ben Brownlee (12*).
Peter Forkin (1-17), Cian Egerton (1-19) and Luke O'Reilly (1-34) were the successful bowlers for the Southern side.
The competition continues when the NCU take on their NW counterparts on Sunday June 10th at Wallace Park in Lisburn.
The action then switches to North Dublin when the teams will play a further two 40-over games before switching to T20 mode for a further three matches.
U15 Youth Interprovincial
At Terenure CC
Southern XI 92 all out (28.4 overs; Ciaran Sheridan 26, John Devane 13; Jamie Forbes 4-9, Daniel Thorne 2-19, Diarmuid Burke 2-21)
Leinster 98-3 (15.5 overs; Nathan McGuire 28, Jack McGee 17, Craig MacKay 15*, Matthew Lynch 12, Ben Brownlee 12*; Cian Egerton 1-19, Peter Forkin 1-17, Luke O’Reilly 1-34)
Leinster won by 7 wickets