Wayside Celtic sent Monaghan United crashing out of the FAI Ford Cup thanks to Les Flynn's late penalty at the Golden Ball in Kilternan.
The Leinster Senior League team have a history of producing upsets and they moved into the quarter-finals for the first time since 1996.
Flynn's 89th minute penalty did the damage as Ian Callaghan burst through on goal and was dragged down by Ian Malone.
The last man, Malone was dismissed and Flynn made no mistake with an excellent spot- kick.
With a replay in Monaghan looming, Wayside dug deep and were well worth their win.
Man of the match Wayne Callaghan was excellent throughout, putting in a number of crunching tackles that let his opponents know they were in a game.
Wayside have yet to start their league campaign, but the Leinster Senior League side showed no signs of rustiness.
Rob Lucie hit the post with a 25 yard effort after just 15 minutes before Monaghan lost goalkeeper Brendan Kennedy who picked up a muscle injury.
Monaghan did have chances and David Scully was a constant aerial threat, with keeper Colm Kelly making a fortunate block with his head from Don Tierney's cross.
On the stroke of half-time, Tierney launched a piledriver that was too hot for Kelly to handle, but there was no United players on hand to avail and the stopper gathered the ball.
James Hand then brought out the best in Kelly with a fine right-footed drive that was heading for the right corner.
The home team came out stronger in the second half and adapted better to the deteriorating conditions.
Ian Callaghan could have done better when latching onto his brother Wayne's pass, but sub Danny Woods made a good save.
The Kilternan pitch held up to the heavy rain, but the game became scrappier and scrappier with referee Neil Doyle booking five players and dismissing Malone.
Kelly made a good save from Hand once again, and it looked set for a replay before the late flurry.
Delighted Wayside boss Peter Lennon has no preferences for the next round, but felt his team were worth the win.
‘I think over the 90 we probably deserved it. It's a great performance seeing as it's our first competitive match.’
‘We're in the next ground, it's great. We haven't played a league game yet. Four weeks time we've a quarter-final to look forward to, it's brilliant.’
Wayside Celtic: Colm Kelly; Kenny Simpson, Wayne Callaghan, Alan Sharkey, Les Flynn; Paddy Byrne (Stephen Flynn 69), Rob Lucie, Caleb Murray, Alan Pratt (Glen Brien 86); Mark Hanlon, Ian Callaghan.
Monaghan United: Brendan Kennedy (Danny Woods 28); Paul Whelan, Conor McMahon, Aaron Mooney, Kevin Williamson; Ian Malone, Don Tierney, McCrossan, James Hand (Reilly 84); Eoin Lanigan (Haran 64), Scully.
