The NW produced an excellent display to beat the NCU in a low scoring game, while Leinster produced a strong performance to defeat Munster in the opening games of the T20 portion of the Under 17 interprovincial series.
Morning rain saw both scheduled games abandoned, but both afternoon games were played with a slight twist - Seapark hosting both fixtures played back-to-back.
The NCU had clinched the 50-over section earlier in the week, but they were stunned by the NW with spinners Ben Mills (4-17) and Conor King (3-8) doing the damage as they were skittled for 72.
The NW had a nervy chase, but won by four wickets with Mills (19*) and Robbie Millar (10*) getting them home in the penultimate over, despite the best efforts of Michael Glass (2-11).
In the first game, a century stand between Mikey O'Reilly (66*) and Jack McGee (34*) helped Leinster post 153 for 3.
That proved far too much for Munster who were dismissed for 37, with Cillian McDonnell taking 4 for 5 and Owen Graham 3 for 4.
No official decision has been taken on whether the two abandoned games will be replayed on Thursday.
If they aren't played then Thursday morning's match between Leinster and the NW will be a winner takes all affair at Seapark, Holywood.