Grosvenor GS 42 Cambridge House 12: Grosvenor Grammar produced a five-try second-half performance to power their way past Cambridge House in the first round of the Danske Bank Schools' Cup.
The home side enjoyed swathes of possession in the first half but turned round leading only 14-5 thanks to some resolute defence from Cambridge House.
The second half proved another matter however, and a dominant Grosvenor set-piece saw their forward pack utilise a highly effective rolling maul to create four more tries.
Victorious coach Kyle McCallan said: "We're obviously pleased as any cup win by that margin is always very satisfying.
"We're a bit disappointed with the two scores that we conceded but on the whole it was a pretty strong performance.
"We have room for improvement in our decision-making but our line-out worked very well, our maul worked very well and our number 10, Mark Johnston, had a good game in terms of creating things."
The east Belfast school's reward is a home tie against Bangor Grammar and McCallan believes his side will be a formidable test for anyone on their own patch.
"We set our stall out for a cup win, and that's what we got. Anyone at home is a good draw for us and if we play like we did today then we're not an easy side to play against no matter who you are," he added.
Cambridge House coach Maurice Finlay was equally pleased with his side's improved showing after a comprehensive defeat at the same venue earlier in the season.
"I'm really proud of the boys and I couldn't have asked for any more from them," he said.
"The intensity was there and I would guess that Grosvenor weren't expecting that from us.
"We came off second best in terms of the result but we can be pleased with how the game went, especially how we stayed in it during the first half."
The early morning kick-off ensured that a light covering of frost remained on the pitch at the outset, with conditions less than ideal for handling.
As a result, Grosvenor's attempts to move the ball around did not see their early possession translated into points and the game remained scoreless until the tenth minute.
A jinking run from Zac Smith produced the game's first tryas the elusive inside centre left several would-be tacklers grasping at air on his way to a fine individual score that was converted by wing Jordan McDowell.
The same pair combined again 10 minutes later to double the lead after Smith rounded the corner from distance to dot down underneath the posts and McDowell made no mistake with the extras.
Cambridge House, to their credit, rallied and with less than five minutes remaining before the break inside centre Thomas Wilson, who excelled throughout, pounced on a loose ball and streaked clear from deep inside his own half to score.
After the turn, Grosvenor's pack came to the fore and within 10 minutes of the restart James Cartlidge had forced his way over the line following a rolling maul and Smith completed his hat-trick.
A loose scrum from Grosvenor then produced an opening for Cambridge which was exploited expertly by Wilson, the visitors stand-out performer, who led the break before offloading to Andrew Whann who finished off the move.
Stuart Gillen was on target with the conversion this time and Grosvenor's lead was again just nine points.
But the Ballymena school were overwhelmed in the last 20 minutes, starting with another rolling maul that saw Karl McLean emerge from the pile with credit for the try.
Cartlidge then produced a carbon copy of his first score to power over in the right corner while a fine sidestep from Mark Johnston allowed the out-half to notch the last try late on.