John Matchett's brilliant 118 secured a Lagan Valley Steels semi-final berth for CIYMS with a 57-run win against Muckamore at Belmont.
The CIYMS opener struck 15 fours and 3 sixes in his superb 68-ball knock, sharing an opening stand of 94 with Chris Dougherty (29).
South African professional Matt McGillivray struck 2 sixes and 2 fours in a quickfire 26 from just 11 balls which propelled CIYMS to an imposing 186 for 4.
The Muckamore chase never got going as two wickets apiece from opening bowlers Allan Coulter (2-11) and James Cameron-Dow (2-27) set the tone for the innings.
Fahad Iqbal top scored with 43 from 34 balls (3 fours, 2 sixes), but Muckamore finished well short on 129 for 7.
CIYMS now face an away trip to Waringstown, while North Down host CSNI in the other semi-final, pencilled in for Friday July 13th, with the finals day at Waringstown on Sunday July 22nd.