With the wind behind them, Ballymena started the match strongly and put early pressure on the reigning champions' defence. Ballymena's winger, Ben Neely, received an early warning from referee, Chris Busby, after celebrating a hefty tackle that put an RBAI winger into touch.
However as Ballymena strung together some phases in the RBAI 22, Alexander Carson's pass was read and intercepted by James Kerr, who had the pace to race the length of the pitch to open the scoring. Winger, Alex Place, converted to send the Belfast boys into an early 7-0 lead.
Place would have the chance to add another three from the tee after a penalty in the Ballymena 22, however his kick was wide against the wind.
Determined to hit back, Ballymena's Carson made an impressive carry from his 22 that resulted in a penalty. From the pen, Ballymena scrum-half, James McIlroy, picked a great delayed pass to Daniel Vercoe-Rogers, who slipped in past two RBAI players to dart under the posts. Robbie Coleman's conversion levelled the score.
McIlroy's game management was impressive as the nine, piled the pressure on RBAI again with a well executed box kick into touch in the RBAI 22.
Following multiple phases, Ballymena got their second through tighthead prop, Deon Fleming, who dotted down after a drive to the line. Coleman added the extras.
In an enthralling half, RBAI hit straight back, with number eight, Adam Boyd, finishing off an attack with a one handed stretch to the line. Place's conversion made it all square as both teams headed into the sheds.
HT: 14-14
With the weather getting worse at Kingspan Stadium, the wind and swirling rain made it tricky for both sides with the greasy ball.
RBAI were made to defend in the early stages with Ballymena pushing early on. RBAI's Lorcan Donnelly making an excellent turnover to slow Ballymena down.
Ballymena had the chance to race into the lead after a foot race between their captain Michael McLean and RBAI's Alex Place, however as McLean waited for the ball to settle, centre Daniel Vercoe-Rogers dived to gather and inadvertently helped knock the ball on.
Ballymena didn't let their heads drop following the miscommunication, as they forced RBAI into a penalty deep in their 22. However RBAI managed to turn it over and ease the pressure.
The Belfast boys pushed forward and worked hard to grab the game-winning third score.
Replacement prop, Ross Dillon, made the difference, as he grounded the ball from an attacking maul. The score was reward for the pressure the RBAI team were putting on Ballymena's defence.
With ballymena chasing the game, RBAI showed the defensive nous to their game. A yellow for Blake McClean after a high tackle on number eight, Charlie Hargy, might have made a few nerves felt, however the RBAI team ran done the clock well and produced a huge lineout steal towards the end of the contest to see out the victory.
As Chris Busby blew his whistle for full-time, the RBAI players charged towards the Nevin Spence stand to celebrate with their year group, who will have sore voices in the morning.
FT: 21-14
Scorers
RBAI:
TRY: Kerr, Boyd, Dillon
CON: Place x3
Ballymena Academy:
TRY: Vercoe-Rogers, Fleming
CON: Coleman x2
Player of the match - Adam Boyd
Teams
RBAI:
(1-8) Zak Molyneaux, Euan Paterson, Blake McClean, Loughlin Sweeney, Milo Carter, Lorcan Donnelly, James Clark, Adam Boyd;
(15-9) Joshua Gibson, Alex Place, Fraser Cunningham (C), Charlie O'Connor, James Kerr, Charlie Gray, Callum Soper
Replacements: Ross Dillon, Reagan Lath Amou, Rory O’Connor, Scott McElhinney, Patrick McEvoy, Luke Gibson, Ben McCausland, Connor Patton
Ballymena Academy:
(1-8) Matthew Wright, Callum Mustoe, Deon Fleming, Conan Scullion, Joshua Gallagher, Harry Lamont, Reece Williamson, Charlie Hargy;
(15-9) Sean McKay, Ben Neely, Daniel Vercoe-Rogers, Alexander Carson, Michael McLean (C), Robbie Coleman, James McIlroy
Replacements: Ben Millar, Joshua Harvey, Henry Casson, Daniel Hayburn, Matthew Cahoon, Reuben Allen, Mark Glenn, Callum Irvine.