CIYMS came out on top of a keenly contested and hugely entertaining Belfast derby against an ever-improving Cooke side at Shaw's Bridge last weekend.
Graham Cloke's side entered the match-up as clear favourites but the hosts impressed for large periods and CI did not make the game safe until Robin Brown's late try, a score that would ultimately deprive Cooke of even the scant consolation of a losing bonus point.
The contest concluded with CI attempting to add to their trio of tries and ensure a five-point return but it was a scenario that had seemed wholly unlikely for much of the second half when they were forced to repel wave after wave of Cooke attacks with two men short of a full complement following yellow cards for Ross Hackney and Paul McVitty.
Speaking after the game, victorious captain Stuart Fergusson commented: "Two Belfast sides going against each other are always going to be trying to get a scalp.
"It was going to be interesting with 13 men, and they were hitting our line pretty hard, but we managed to hold on and get away with the win."
CI began the game on the front foot and, when Phillip Doherty was penalised for a late hit on scrum-half Michael Wilson, they made their intentions clear by eschewing the chance for a certain three points and opted instead to kick for the corner.
The subsequent lineout, however, produced the first indication that CI were not to have things entirely their own way as Graham Jewhurst stole the ball to end the threat.
When Michael Johnston was penalised five minutes later for not rolling away, CI this time chose the more pragmatic option and allowed out-half Matt McGuigan to kick them into a three point lead.
Despite the deficit, Cooke began to show flashes with the ball in hand and when the dangerous Alan Gourley darted forward, a quick interchange of passes between the out-half and Stephen Mooney created sufficient space for Doherty to go over in the corner.
CI retook the lead as the game entered the second quarter when a barnstorming break from Mark Scott gained valuable ground before he offloaded to McGuigan having been halted short of the line.
The young out-half in turn released Wilson who, by cleverly using McVitty outside him as a decoy, was able to dart between the last two Cooke defenders and make the score 8-7.
A successful penalty from Gourley after CI were pinged for coming in at the side saw yet another change in momentum and, after McGuigan pushed an opportunity to respond across the face of the posts, Cooke were able to hold on to the lead until the break.
In an attempt to reverse their fortunes, CI replaced Matt Armstrong with Ross Hackney for the second half but the substitute received a yellow card within five minutes.
The numerical disadvantage did not stop the visitors taking the lead however, Mark Scott capping off his impressive individual performance with a try after 51 minutes.
When Paul McVitty was shown CI's second yellow of the day, leaving the side with 13 men for a time, a frantic period of play followed but heroic defending kept Cooke from breaching their line.
The home side did temporarily level matters just as their opponents were returned to 15 men, but McGuigan restored the lead with another penalty in the 70th minute.
With the game becoming an increasingly tense affair, tempers flared after Brown appeared to be struck on the ground but the full-back would exact the best possible form of revenge when his late try, after good work from Paul McCausland, sealed victory.