The NCU beat Leinster by five runs in a thrilling Under 13 interpro contest at Stormont to go 2-0 up in the four match series.
A solid batting performance saw the NCU make 191 for 7, with contributions throughout the top order. Finn Lutton top-scored with 45, while Ryan Hunter (38), Harry Dyer (23), Tom Crothers (19), and Sam Allister (16) all chipped in.
A fifth wicket stand of 94 between Macdara Cosgrave (57) and Matthew Langan (41) saw Leinster to 131 for 4 in the 30th over and on course to level the series.
However, the NCU fought back well with three wickets apiece for Jude Keates and Harry Dyer, which saw them gain victory by just five runs in a game which ebbed and flowed throughout.
The teams are back at Ringcommons on Thursday before the series finishes at Stormont again on Friday.