Shane Dadswell was the difference as Instonians beat CSNI by 8 runs in the afternoon semi-final.
The South African professional cleared the ropes six times on his way to a top-score of 64 as Inst made 158 for six - runs too for Cian Robertson (30*). Matthew Foster was the pick of the bowlers taking 2 for 16.
Early wickets for James Magee and Cian Robertson meant CSNI were always chasing the game as the required rate climbed. Adam Leckey (40*) and Ryan Hunter (27*) got them close but it always just out of reach.
Cliftonville Academy invoked the 'Spirit of 95' as they reached the final of the T20 Cup for the first time as they beat five-times champions CIYMS by four wickets.
The Belmont side were in a relatively decent position at 51 for 1 in the 8th over, but collapsed alarmingly losing 9 wickets for 49 runs to be all out for 100.
Ben Kane and Jared Wilson each took three wickets, while Abhishek Raut took two.
Raut (19) and Francis Collins got the chase off to a good start with an opening stand of 43, but the introduction of Alex Armstrong changed the complexion of the match. The teenager took two wickets and deflected a Wilson drive onto the stumps to run out Raut who had strayed out at the non-striker's end.
Suddenly it was 72 for six and anybody's game. John Glass (21*) and skipper Matthew McCord got the 29 needed - both hitting vital boundaries to seal the win off the penultimate ball.
In the T20 Trophy, favourites Carrickfergus crashed out in a surprise loss to Bangor after they were bundled out for just 88 at Sandy Bay.
Chris Pyper and Angus Farrell each took three wickets, while there were two for Manav Chhabra. Alex Haggan (36) and Anthony Martin (20*) were the best of a bad lot for Carrick.
Sam McMillan's 33 at the top of the order ensured no get out of jail card for the Middle Road side as Bangor eased to a seven wicket win with five overs to spare.
Cregagh eased to comfortable 9-wicket win over Donacloney Mill in the first semi-final at Larne. DM managed 120 for 9 with 20's for Craig Kennedy, Judd Markham and Shane Warren.
Max Shannon took 2 for 9, and there was also a brace for Alastair Watt and Adam McCormick. It was the captain McCormick who was also to the fore with the bat, hitting 3 fours and 2 sixes in a 48-ball unbeaten 61, adding an unbroken 90 for the second wicket with Jonny Moore - who hit four boundaries in his 44 not out - as the win was sealed with 13 balls left.