Inst now targeting the double after retaining Medallion Shield
RBAI 13 - 5 Wallace High
Inst built up a two score advantage and then closed the game down to retain the Danske Bank Medallion Shield at Kingspan.
The Belfast boys are now on course for the 'double' which has only been achieved twice this century - by Campbell College in 2002 and Methodist College in 2013.
Inst Director of Rugby Daniel Soper was thrilled with the outcome, a result which keeps spirits high ahead of the Schools' Cup showdown with Wallace High on St Patrick's Day.
"We were content with the eight point advantage but then we let in a soft try at the wrong time," said Soper.
"Fortunately we didn't miss many tackles after that and especially in the final ten minutes when Wallace were pressing.
"It was a hard earned win and part of that was the fact that we coped with the difficult wind better than our opponents."
It was not a great opening for the holders as the initial kick was kicked dead which gave Wallace a scrum on halfway.
Inst soon regained their composure and after a few minutes took the lead when David Lyttle kicked a penalty directly in front from 30 metres out. It was stalemate for a time before Lyttle hit the post with a second penalty attempt.
Niall Armstong had been gaining territory but just before the interval Inst extended their lead. Their No 8 and captain Ethan Glover handed off a couple of defenders to crash over.
Lyttle again hit the post with his conversion attempt. The Lisburn team fought back to reduce the arrears when out-half Conor Rankin cut through and ran around the full-back to touch down and make the half-time score 8-5.
Inst added their second try following an accurate penalty for position. From the line out close to the '22' the ball was swung along the back line and winger Kyle McComiskey dashed in to give his team a comfortable lead.
With 20 seconds remaining there were a couple of players prostrate on the pitch and following an eight minute delay the final whistle was blown.
Kiwi Soper thought it was a competent all round performance with a few players showing up well. "Ethan Glover tackled ferociously and made many yards.
"David McCann in the centre was a danger in attack and strong in defence."
RBAI: J Starrett, C McCormick, A Stewart, J Gilchrist, N Ryan, T Lyons, E Sloan, E Glover, N Armstrong, D Lyttle, K McComiskey, J Heyburn, D McCann, J Hutton, S McMaster Replacements: C Knocker, A Adair, P Simpson, J Arbuthnot, M Fleetman, J Metcalfe, R Glasgow, J Mullan
Wallace High: N Blaine, S Cardosi, J Waite, M Kenny, J Brown, R Beckett, D Sedge, B Morrison, M Smith, C Rankin, J Dillon, J Warke, J Cardosi, T Bradley, J Peters. Replacements: J Ferguson, J Haggan, J Hayes, A Parker, T Wiggan, B Smyth, J Morrison, P McRoberts
Referee: Adrian Reavey.