Friday's Schools' Cup Final will be an all Inst. affair as the First XI brushed aside the challenge of Wallace High School in the second semi-final.
They will now come up against their Second XI who recorded a surprise victory against Campbell College in the first semi-final played last week.
It was indeed a day to remember for RBAI, and Thomas Johnston in particular as he scored a century to secure his side's place in the decider.
Johnston's 127* was the highlight of an Inst. innings and with Adam Ly adding 42 the Belfast school rattled up a massive 40 over total total of 247/5.
Thomas Johnston at Osborne Park: Pic Owen Lambert
For Wallace only Max Kamaralajara managed more than a single wicket, his 2-32 the best return on their side.
The Inst. win was assured when James Rose took 4-25, Stuart McCollum's 23 the only notable score on the Wallace side.
There were two wickets each for Robert Craigan (2-8) and Adam Wylie (2-29) as the visitors subsided to 127 all out thus giving Inst the victory by 120 runs.
The Final will be held at Osborne Park on Friday 25th June with a 10am start time.
Schools' Cup Semi-Final Result:
RBAI beat Wallace High School by 120 runs, Osborne Park, 21 June.
RBAI 247-5 (40 overs, T Johnston 127 no, A Ly 42, M Kamaralajara 2-32)
Wallace High School 127 (S McCollum 23, J Rose 4-25, R Craigan 2-8, A Wylie 2-29)