Ballinamallard defeated Glentoran in a penalty shoot-out after the League Cup quarter-final ended 1-1.
The Mallards took the lead through Johnny Lafferty's deflected effort in the 14th minute at Ferney Park.
Glentoran brought the match into extra-time courtesy of a Curtis Allen strike on 76 minutes.
Liam Martin struck the winning spot-kick as the Mallards won the shoot-out 4-1 to secure their first ever cup victory over the Glens.
Johnny Currie had the first chance for Ballinamallard after seven minutes following some impressive build-up play but he saw his shot tipped over by Elliott Morris.
Mallards broke the deadlock through Lafferty's deflected shot, after David Kee and Christopher Crilly combined well down the right flank.
The home side were good value for their lead and continued to dominate as Ryan Campbell went close to doubling the advantage immediately, but his header looped over the bar.
Glentoran looked dangerous on the counter-attack and should have equalised through Allen when he was clean through on goal, but his weak shot did not trouble Stefan McCusker.
The visitors threatened again just before the interval as 19-year-old Jordan Stewart broke through the Mallards defence with pace and got his shot in before Ballinamallard cleared the danger.
Eddie Patterson's men started the second period strongly and piled pressure on the Mallards defence, with Allen again squandering an opportunity by heading over after a pinpoint cross from Fra McCaffrey.
Moments later, Stewart cut in from the left and tried his luck but his driven shot was blocked and scrambled clear to give Mallards a brief reprieve.
Glentoran's pressure paid off when they broke clear and McCusker could only parry Danny McKee's shot to Allen, who made no mistake from close range.
There could have been a last-minute winner for Glentoran to break Ballinamallard hearts but Stewart's cross to the far post lacked accuracy and was too high for Allen to pounce.
Allen then had a goal disallowed for offside in extra-time and the Glens were unable to edge ahead as the game went to penalties.
In the shoot-out Jason McCartney, Lafferty, Raymond Foy and Martin all converted for Ballinamallard while Allen and Stewart missed before Niall Henderson scored the only Glentoran spot-kick.