Shane O'Neill scored deep into stoppage time to secure a famous victory for Cabinteely over UCD in their first ever League Cup fixture at the UCD Bowl.
It was the merest of slivers that separated the sides following a match that rarely threatened to get going before suddenly and spectacularly bursting to life with five minutes to go.
The goal ensured Cabinteely's League of Ireland housewarming party – which saw one of the bigger crowds to descend on Belfield in recent times – will continue unabated for at least another few days.
The game was all set to drag on for another 30 minutes on a bitterly cold, windy night in Belfield, when a loose ball in midfield was pounced upon by the impressive Evan Finnegan who, with the retreating UCD defence in disarray, calmly played in O'Neill.
Finnegan had missed an almost identical chance moments earlier when Conor Mackey steered his left-foot strike brilliantly onto the post. O'Neill made no mistake second time around and Mackey could only deflect it into the corner of the net to the delight of the majority visiting crowd.
It was perhaps a little more than the visitors deserved having spent large spells of the game on the back foot. It was just reward, however, for Cabo coach Eddie Gormley, who made the more positive changes in the second half when he introduced O'Neill and striker Ger Pender.
With a turnover of less than 48 hours between games, UCD manager Collie O'Neill made eight changes to the team who started in Cobh on Saturday. Chris Mulhall and Gary O'Neill were the only two players to keep their places.
Cabinteely manager made just two changes to the side that overcame Wexford Youths on the opening day. Striker Bobby Mazono and winger Tyrone McNelis replaced Pender and Jordan Buckley.
There were barely two minutes played when UCD registered the first shot of the evening as Chris Mulhall slipped in behind Cabinteely full-back Jamie McGlynn, but his near-post effort was easy for Evan Whelan to bat away.
UCD's midfield – in particular teenage debutant Daire O'Connor – knitted together some tidy passages of play but those frequently broke down once the ball reached Mulhall, who was perhaps feeling the effects of two full games in 48 hours.
Samir Belhout was having a quieter night on the left hand side for the Students, but it was he who produced the one moment of real quality late in the half, his diagonal ball only just evading the onrushing O'Connor when any touch would have produced the game's first goal.
Cabinteely had fewer clear-cut opportunities to show for their willing endeavour. Striker Bobby Mazono had a half-chance in the opening minutes when the ball briefly fell to him amid a penalty box scramble, while Evan Finnegan saw his deflected left-footed shot loop over the Students' crossbar.
Collie O'Neill will have felt his UCD players hadn't done enough to capitalise on their possession advantage in the first half, and they increased the intensity after the interval.
O'Connor – who was at the centre of most of UCD's positive play – produced a beautiful piece of skill on the turn and volleyed powerfully from 20 yards, but his shot was straight at Whelan, and the Cabinteely keeper held at the second attempt.
They couldn't maintain that initial surge, however, and Cabinteely looked the fresher side as the tie drifted into the final quarter, and Finnegan again should have done better when he skied a glorious chance from inside the box.
Extra time seemed inevitable, until a darting run from Mulhall drew a tired lunge from Cabinteely defender Jamie McGlynn. Referee Ben Connolly paused a moment to consider before calmly pointing to the spot.
A goal at that stage would likely have killed Cabinteely's resolve, but Whelan dived decisively to push Eoin Kirwan's firmly-struck drive onto the post – as good a penalty save as will be seen around the country this season.
Cabinteely, sensing the Students' heads had dropped, took the initiative from that point, and the home side were grateful to Markey for an excellent save at close quarters from Finnegan.
It all seemed set, then, for another 30 minutes' play, but O'Neill's calm finish in the third minute of injury time means they'll have bragging rights in Dun Laoghaire/Rathdown until the side’s league game in Stradbrook on April 10th.
UCD AFC: Conor Mackey; Dan Tobin, Ryan McLaughlin, Maxi Kougoun, Sean Coyne; Gary O'Neill, Eoin Kirwan, Daire O'Connor (Greg Sloggett 90+2), Chris Mulhall, Samir Belhout (Dylan Watts 68); Ryan Swan (Conor Cannon 75).
Subs Not Used: Niall Corbet (gk), Adam Harney, Troy Carey, Jamie Doyle.
Booked: O’Neill (40).
Cabinteely FC: Evan Whelan; Lloyd Cairns, Victor Ekanem, Robert Moloney, Jamie McGlynn; Evan Finnegan, Tyrone McNelis (Shane O'Neill 60), John McKeown, Aaron Brilly, Kevin Knight (Conor Foley 12); Bobby Mazono (Ger Pender 60).
Subs Not Used: Shane Fagan (gk), Jordan Buckley, Eoin O'Sullivan, Gavin Fahey.
Booked: Brilly (28), McGlynn (85).
Referee: Ben Connolly.
Player of the Match: Evan Finnegan (Cabinteely FC).