There was nothing to separate the teams in a stalemate with Insta moving into the final after a 4-2 shoot-out victory.
Catholic Institute will defend their Irish Senior Cup title in the final after they bested Railway Union after penalties in their last four encounter in Rosbrien on Sunday afternoon.
After defeating Pegasus 4-1 in league action the previous day, the Limerick side held out for a second successive win to bookend the perfect weekend.
On Sunday, there was nothing to separate the teams in a stalemate with Insta moving into the final after a 4-2 shoot-out victory.
They will meet Monkstown in the April 29 final after they saw off Avoca 2-1 on the same afternoon at home. The final will take place in Belfield next month.
In Limerick, after 70 minutes, neither was able to break the deadlock, with both having played domestically the previous afternoon. The tense stalemate made way for a thrilling shooutout where Insta were perfect in their shuttles to move one step closer to retaining the title they won for the first time last year.