CSNI joined Waringstown in the next round of the Irish Senior Cup - with the five other NCU clubs all crashing out.
CSNI made light work of Balbriggan, beating their Leinster counterparts by nine wickets at Stormont as Andre Malan continued his fine form by hitting 65.
Bowling first, CSNI bowled their opposition out for 140 and chased it down with minimal fuss as Andrew Cowden ended on 38 and Marc Ellison the only man dismissed for 27.
It means the Belfast club continue their unbeaten run in cup competitions having recorded their first league win of the season on Saturday.
Muckamore won by one wicket in the first round, but were beaten by one run this time round by Strabane.
Sri Lankan overseas player Chathura Pieris top scored with 66 in a total of 233 for the hosts before he was caught behind off the bowling of Aditya Adey, who picked up two wickets in the 22nd over.
Adey then scored 42 in reply whilst captain Neil Gill contributed 38, but it wasn’t enough for the Antrim club to progress.
A Nigel Jones century wasn’t enough for CIYMS to beat last year’s finalists Merrion as the Belmont side were beaten by 11 runs.
Merrion set a big total of 273-nine, with recently retired Ireland batsman Ed Joyce scoring 78 before he was ran out by Trevor Britton and South African professional Matt McGillivray taking with four wickets.
Jones hit 109 in reply and it looked like they were going to pull off a fantastic run chase, but they fell just short.
Carrickfergus hosted Leinster at Middle Road in a rain affected game and scored 174- six in 36 overs with Alex Haggan hitting 61 and Daniel Poulton scoring 45.
The score was reduced to 116 needed from 20 overs and the visitors chased it down with ease, winning by seven wickets.
North Down were well beaten by Pembroke, who batted first and scored a mammoth 347-5 in their 50 overs, with a first wicket stand of 207.
Fiachra Tucker scored 116 while Diarmaid Tucker also contributed 93 as North Down struggled to get a grip on the match at all, eventually being bowled for 131 and going down by 216 runs.
Instonians were beaten by seven wickets by Dublin-based side Phoenix at Shaw’s Bridge.
They batted first and ended up on 273-5 from 46 overs with Shane Getkate hitting 42 from 26 balls late in the inning.
Rain arrived with Phoenix sitting on 38/0 after seven overs played and the score was therefore recalculated to a target of 200 in 29 overs.
Sitting on 149/2 with nine overs to play, they reached the target with three overs to spare, knocking out last years semi-finalist’s in the process.