The dreaded bowl-outs came into play at both Coleraine versus YMCA and Waringstown against Railway Union.
YMCA were on 29-3 after 10 overs when a downpour of biblical proportions flooded the ground, leaving the umpires no option.
David Cooke and Gareth Burns hit for the home side, but YMCA also hit twice to take it to sudden death.
Kyllin Vardhan held his nerve to strike the stumps and send Coleraine into the last eight 3-2 winners.
At The Lawn, Railway Union had reached 65 for 2 in 15.2 when play was halted. Despite an intense mopping up session, a bowl-out was required to settle the tie.
James Hall hit to put the home side 1-0 up, but Saad Ullah, Dhruv Kapoor and Kevin O'Brien all struck to give the visitors a 3-1 win.
They're proving the shoot-out specialists, having progressed in the previous round against Instonians in the same fashion.
Ryan Haire's unbeaten 70 (8 fours, 3 sixes) helped North Down canter into the last 8 after they beat Phoenix by 7 wickets.
James Cameron-Dow took 3 wickets as Phoenix could only manage 132 - never defendable at Comber.
Pembroke ended the Cork County fairy tale, with a 55 run win in a 45 over game.
The Sydney Parade side turned in a solid batting display as 5 players scored 30 plus - skipper Theo Lawson anchoring their innings with an obdurate 44.
The Pembroke total of 219-6 was beyond Cork who finished on 164 all out - Robert Duggan top scoring with 34, before becoming one of three wickets for 3 year-old leg-spinner JJ Garth (3-36).