RBAI outscored their opponents by three tries to one with Iain Jones, Nathan Brown and Rory Bell all crossing the whitewash in response to three Jack Irvine penalties.
The game started at a frenetic pace with both teams looking to spread the ball wide and offload at every opportunity. The majority of the first half was played in the middle third of the pitch but despite Ballyclare enjoying most of the possession; it was RBAI who opened the scoring.
Left winger Rory Campbell collected his own Garryowen and produced a neat pass to inside centre Bell, who in turn fed Jones and the speedster ran in from 40 metres out. Brown was unable to add the touchline conversion.
Ballyclare HS responded well with captain Jonny Darling and prop Paddy Reid carrying strongly and outhalf Irvine was orchestrating the attack well. Indeed, Irvine almost created a try with a superb line break and pass to send fullback James Beattie down the touchline, only for him to be ushered into touch five metres out by his opposite number Fraser Wright.
Irvine did manage to register his side’s first points on the half hour mark, when after a mix up in getting a kicking tee onto the pitch for a penalty; he dropped a goal to reduce the arrears to 5-3. Irvine was enjoying a purple patch at this stage and another fine run should have put James McKee under the posts but the winger failed to hold the scoring pass.
Half time: RBAI 5 - 3 Ballyclare HS
RBAI started the second period well and scored another try five minutes after the break when Brown cut an excellent angle from a John McClure pass and sliced through the Ballyclare defence. Brown was again wide with his conversion attempt but his side now held a seven point advantage.
Irvine and Campbell traded penalties to take the score to 13-6 with ten minutes to play. The Ballyclare threw everything at the Inst and were rewarded with another Irvine penalty, his third of the afternoon, to make it a four point game.
But heroic defence from the entire RBAI team and astute tactical kicking by outhalf McClure kept the danger at bay and it was the Belfast side that had the last say with a try from Bell.
Inst will now face the winners of Wednesday’s semi-final between Methody and RS Armagh in the Danske Bank Schools' Cup Final on Monday 18th March.