Two emphatic wins in the T20 format ensured Leinster clinched the U15 title with a day to spare, beating the Southern XI and NCU at Rush.
The title is the 11th for Leinster coach Brian O'Rourke, assisted this season by Stephen Doheny and Daniel Coffey.
Three wickets for David Vincent and two apiece for Daniel Thorne and Diarmuid Burke saw the Southern side dismissed for just 90.
Leinster knocked off the modest total in just eight overs with Nathan McGuire (44*) and Matthew Lynch (36) both in the runs.
In their second game Leinster piled on the runs spearheaded by Nathan McGuire's 85 from just 45 balls, which included 16 fours and a six.
Wilhem De Klerk then ensured the total would be over 200 as he clubbed 7 fours and 3 sixes in his 56 from just 21 balls - Leinster finishing on 225 for 6.
The NCU reply was never up with the daunting required rate, but Adam Wylie (35), Matthew Humphreys (27) and Matthew Daly (25) ensured respectability as they made 132.
Merrion's Hugo Neville took the bowling honours with his haul of 5 for 21.
The NW were involved in the two closest finishes of the day.
Playing the NCU at The Hills, Wylie (38) and Humphreys (31) shared an opening stand of 56 as the NCU posted 126.
Robbie Millar (3-26), Tom Harpur (2-15) and Raymond Curry (2-27) the main wicket takers.
Craig Doherty hit 36 to give the NW hope, but three wickets from Matthew Humphreys and three run outs saw them fall two agonising runs adrift.
There was better fortuens for them in the afternoon game, as Robbie Millar made 39, Craig Doherty 22 and Tom Harpur 20 in their total of 124 - two wickets each for Killian McGrane and Abdulla Tariq.
Tariq (49) and Ciaran Sherdan (42) looked to have won the match with a second wicket stand of 80, but they lost their way in the closing stages and the NW prevailed by four runs.
The final round of matches takes place on Friday, when Leinster play the NW at Balbriggan, and the NCU face the Southern XI at North County. Action in both matches starts at 11am.
At Kenure, Leinster beat Southern XI by 9 wickets
A Tariq c McGuire b Burke 8
A Tonge not out 23
H Thompson b Burke 19
L Whelan b Vincent 7
C Egerton c Thorne b Brownlee 2
A Shah b Thorne 1
C Sheridan b Vincent 4
B McBride c&b Vincent 1
J Devane c De Klerk b Thorne 12
Extras (13w) 13
Total (8 wkts, 20 overs) 90
Fall: 1-8 2-28 3-41 4-45 5-51 6-54 7-61 8-90
Bowling: D Thorne 4-0-30-2; J Forbes 2-0-10-0; B Brownlee 4-0-24-1;
D Burke 3-0-6-2; W De Klerk 3-0-13-0; D Vincent 4-1-7-3
N McGuire not out 44
M Lynch c O'Reilly b Shah 36
T Tector not out 5
Extras (4b, 1lb, 3w) 8
Total (1 wkt, 8 overs) 93
Did not bat: B Brownlee, J Forbes, W De Klerk, D Burke,
J McGee, D Thorne, C McKay, H Neville, D Vincent, P Morris.
Bowling: C Egerton 2-0-27-0; K Shetty 2-0-19-0; A Shah 2-0-18-1; P Forkin 2-0-24-0
At The Hills, NCU beat NW by 2 runs
M Humphreys lbw b Millar 31
A Wylie run out (Curry/Millar) 38
M Daly c Harpur b Kyte 0
A Ly b Millar 2
B Beattie b Harpur 14
M Waite st Hall b Millar 6
J Lambert c Millar b Curry 2
A Kennedy b Harpur 0
M Halliday not out 14
S Burke b Curry 7
J Rose run out (Hall/Kennedy) 4
Extras (4b, 2lb, 2w) 8
Total (all out, 20 overs) 126
Fall: 1-56 2-59 3-67 4-78 5-91 6-98 7-98 8-98 9-119 10-126
Bowling: T Harpur 4-1-15-2; S Kennedy 4-0-25-0; C Kyte 4-0-27-1;
R Millar 4-0-26-3; R Curry 4-0-27-2.
S MacBeth lbw Humphreys 5
C Doherty c Burke b Wylie 36
R Millar c Hallliday b Daly 4
R Curry st Beattie b Humphreys 14
S Kennedy c Daly b Humphreys 4
R McLaughlin run out (Humphreys) 1
C King run out (Humphreys) 14
T Harpur run out (Beattie) 16
B Crumley not out 2
Extras (1lb, 26w, 1nb) 28
Total (8 wkts, 20 overs) 124
Did not bat: C Kyte, K Hall
Fall: 1-25 2-47 3-72 4-79 5-81 6-81 7-119 8-124
Bowling: M Waite 1-0-12-0; M Humphreys 4-0-24-3, J Lambert 4-0-23-0;
M Daly 4-0-12-1; M Halliday 4-0-32-0; A Wylie 3-0-20-1
At Milverton, The Hills, NW beat Southern XI by 4 runs
C Kyte c Devane b O'Reilly 0
C Doherty c McBride b Forkin 22
R Millar b Tariq 39
R Curry lbw Thompson 3
T Harpur b Tariq 20
B Higgins b McGrane 5
S Kennedy not out 6
R McLaughlin b McGrane 4
K Hall not out 3
Extras (21w, 1nb) 22
Total (7 wkts, 20 overs) 124
Fall: 1-1 2-55 3-62 4-98 5-108 6-116 7-120
Bowling: L O'Reilly 4-0-20-1; A Tariq 4-0-24-2; P Forkin 4-0-20-1;
K McGrane 2-0-22-2; H Thompson 4-0-14-1; J Devane 2-0-24-0.
A Tariq b Curry 49
A Tonge c Kyte b Kennedy 2
C Sheridan c Bhavsar b Kyte 42
H Thompson not out 12
L Whelan c Higgins b Kennedy 3
B McBride not out 1
Extras (10w, 1nb) 11
Total ( 4wkts, 20 overs) 120
Did not bat: L O'Reilly, J Devane, P Forkin, K McGrane, K Shetty
Fall: 1-9 2-89 3-112 4-119
Bowling: T Harpur 4-0-32-0; S Kennedy 4-0-16-2; C Kyte 4-0-29-1;
R Millar 2-0-13-0; R Curry 4-0-14-1; K Bhavsar 2-0-16-0.
At Kenure, Leinster beat NCU by 93 runs
N McGuire c Beattie b Waite 85
M Lynch st Topping b Humphreys 6
T Tector c Wilson b Daly 17
B Brownlee b Humphreys 16
J McGee c Daly b Waite 18
C McKay not out 12
W De Klerk run out (Humphreys) 56
Extras (2lb, 13w) 15
Total (6 wkts, 20 overs) 225
Did not bat: J Forbes, D Burke, D Thorne, H Neville, D Vincent, P Morris
Fall: 1-27 2-81 3-131 4-137 5-159 6-225
Bowling: E Wilson 4-0-50-0; M Humphreys 4-0-28-2; M Daly 3-0-40-1; A Kennedy 1-0-9-0;
A Wylie 1-0-19-0; M Waite 3-0-31-2; J Lambert 4-0-46-0.
M Humphreys c Neville b Forbes 27
A Wylie c Tector b Neville 35
B Beattie c Tector b Forbes 0
M Daly c McKay b Neville 25
E Wilson c Neville b De Klerk 9
J Lambert c&b Neville 1
M Waite b De Klerk 0
S Topping c McGuire b Neville 0
J Rose c Vincent b Neville 11
M Halliday lbw Morris 6
A Kennedy not out 10
Extras (1lb, 7w) 8
Total (all out, 18.2 overs) 132
Fall: 1-56 2-57 3-91 4-93 5-101 6-102 7-102 8-102 9-109 10-132
Bowling: D Burke 4-0-32-0; J Forbes 4-0-36-2; P Morris 4-0-22-1;
H Neville 3.2-0-21-5; W De Klerk 3-0-20-2.