It will be an all-NCU ClubTurf Ulster Cup final at Carrickfergus next month after North Down won at Limavady yesterday by seven wickets.
But while the Comber side eased home with eight balls to spare, their opponents on August 21 were decided by the final delivery of yesterday's other semi-final at The Lawn as Instonians gained revenge for their Challenge Cup defeat on the same ground at the same stage.
Waringstown had won the Premier League encounter between the teams 24 hours earlier by 52 runs, but a glance at the line-ups showed the teams had given the games rather different priorities.
While Waringstown's victory on Saturday kept them on North Down's tails - they are four points behind with a match in hand- Instonians, 12 points back, appear to have given up on the league and John Stevenson opted to play yesterday instead of Saturday.
Waringstown were without six of their league team, but what a fright they gave the Belfast side.
When Rory McCann hit Simon Stokes for 12 as Instonians started their chase for 199 and 54 were scored in the first seven overs, it looked as if victory would be a formality for the visitors.
But Lee Nelson (who top-scored on 54) and Kyle McCallan removed Neil Hamilton (33) and Rory McCann (26). Alan Harrison then bowled his eight overs for just 29 runs and also took the wickets of Andrew White (39) and Eugene Moleon (2).
Nelson and McCallan returned to take the wickets of Jordan Morrow and Richard McCarthy and by the time the last over started, Instonians still needed eight to win.
Robbie Kirk hit the first ball for four but was run out off the third. That got James Shannon, who had just brought up his 50, back on strike. Two leg byes and a single were scrambled to tie the scores and umpire Noel McCarey left the field to clarify the result if a wicket fell off the last ball.
That would have left both teams on 198 for nine, but Dominic Reed rendered the rule book academic, edging Simon Stokes' last ball to the boundary to reach the final.
But there will be no repeat of the controversial Irish Cup game between Limavady and Inst.
Ian Moran, with 65 not out from 56 balls followed up Neil Russell's dashing start - 60 off 33 balls with eight fours and a six - to overturn Limavady's 237 for nine. Thomas Riddles top scored with 65 but the Roesiders definitely miss the bowling - not the batting - of suspended Decker Curry.
On Saturday, North Down were equally impressive in passing Carrickfergus's 232 for eight with eight wickets left, with Alistair Shields making a first senior century.