A hat trick of tries for RBAI full-back Joshua Gibson stole the show at Kingspan Stadium, with Alex Place also impressing on the wing for the Belfast school, with a stunning individual try in the opening half.
Wallace made it a competitive match despite the first half scoreline of 26-3, with the Lisburn boys fighting back well in the second half to narrow the scoreline.
The match started off well, with both sides testing each other with high balls in the fight for territory. Wallace started off well, with fly-half, Lewis Stevenson, getting points on the board with an early penalty.
RBAI responded immediately, forcing an early turnover and scoring from a pick and go after a well-executed lineout. Tighthead prop, Blake McClean, powering over in front of the boisterous Belfast support in the Nevin Spence Memorial Stand. Alex Place's kick went wide, but Jamie Kirk's team found themselves in the early lead.
RBAI scored their second try from more good work at the set piece, with another lineout maul in the Wallace 22' getting them close to the whitewash, the ball was then worked out to Joshua Gibson who had the task of running under the posts. Place converted the try to make the score 12-3.
The next RBAI score was stunning, with Alex Place carrying out some brilliant wing play in the Wallace 22', chipping the ball over the Wallace defender and chasing to finish. The try was one of a very confident winger. Place added the cherry on top by converting his own score for a 16-point lead.
Wallace competed to try and muscle their way back into the game, but handling errors would frustrate the Lisburn team and hand possession back to RBAI.
Before half-time, Joshua Gibson notched his second try of the half, after a slick combination with Alex Place out on the right wing. The duo were enjoying themselves out there at the home of Ulster Rugby. Place nailed his conversion and the Belfast school had a commanding 26-3 lead at the break.
Wallace began the half in strong fashion as they looked to get back into the tie. Their side began the half with urgency as they looked to claw back points on the scoreboard.
A lineout maul in the RBAI 22' looked as if it would power the Wallace forwards over, but RBAI's impressive flanker, James Clark, was able to hold the ball up to the delight of his teammates.
Wallace kept their foot on the gas and got their reward, with winger Josh Geddis diving over in the corner to finish well, and grab Wallace's first try of the semi-final. Stevenson was unable to score the conversion from the tricky angle.
As Wallace's tails were up, RBAI once again showed their attacking nous, with scrum-half, Callum Soper, popping off a gorgeous inside pass to the onrushing Gibson, who broke the defensive line to race clear with his speed. Alex Place's conversion extended the Belfast school's lead once again.
Despite the difference in the scoreline, Derek Suffren's team never gave in and battled their way to two tries from replacement prop, Daniel Macklin-Copeland, and winger, Josh Geddis, scoring a second impressive try, fending off pressure to score in the left corner late on.
RBAI's attacking performance had made the difference and at full-time the Belfast side celebrated their win which guarantees them a place in the final on Monday 18 March at Kingspan Stadium.
Tomorrow's semi-final between Ballymena Academy and Sullivan Upper School will determine their opponent.
Scorers
RBAI:
TRY: Gibson x3, Place, McClean
CON: Place x4
Wallace HS:
TRY: Geddis x2, Macklin-Copeland
CON: Stevenson
PEN: Stevenson
Teams
RBAI:
(15-9) Joshua Gibson, Alex Place, Fraser Cunningham (C), Charlie O'Connor, James Kerr, Charlie Gray, Callum Soper;
(1-8) Zak Molyneuax, Euan Paterson, Blake McClean, Loughlin Sweeney, Milo Carter, Lorcan Donnelly, James Clark, Adam Boyd.
Replacements: Ross Dillon, Regan Lath Amou, Rory O'Connor, Scott McElhinney, Patrick McEvoy, Luke Gibson, Ben McCausland, Connor Patton.
Wallace HS:
(15-9) Daniel Wilson, Matthew Dickson, William Sproule, Quinn Armstrong, Josh Geddis, Alex Stevenson, Lewis Stevenson;
(1-8) James Gould, Michael McCavery, Rio McDonagh, Harry Lightbody. Callum Johns, Ben Moore, Jon Rodgers (C), Sam Warwick.
Replacements: James Furphy, Daniel Macklin-Copeland, Ollie Fitzsimmons, Ben Cairns, Rhys Ewing, Dnaiel Hearne, Carter Thompson, Corey Dawson-Stirling.