An Anto Flood brace saw Shelbourne inflict a first defeat of the season on Dundalk as they cut the Louth outfit’s lead at the top of the First Division to just two points at Oriel Park.
In what was a bad-tempered affair, the home side finished the game with just nine men.
The visitors couldn’t have got off to a worse start, as they fell a goal behind after just 20 seconds with teenage striker Tiarnan Mulvenna outpacing captain Damien Brennan to John Flanagan’s punt forward to slot past Dean Delaney.
Delaney then denied the home side a second on 13 minutes when he smothered a shot from Robbie Farrell, and that save was to prove crucial as just two minutes later Dermot Keely’s men drew level when David Freeman curled a free-kick around the wall to make it 1-1.
Just when things started to go well for Shelbourne, they suffered a setback, with former Oriel Park favourite James Keddy receiving his marching orders on 24 minutes for a second bookable offence.
The winger, who won an FAI Cup medal with Dundalk in 2002, almost managed to stay on the field, however, with referee Damien Hancock having to be reminded by the home side’s large support that he had already booked the 35-year-old in the eighth minute.
With the man advantage, John Gill’s side started to lay siege to the visitors’ goal, with Flanagan and Farrell going close with efforts either side of half-time.
It was the ten men of Shelbourne who took the lead on 58 minutes, however, when a mistake at the back by Dundalk captain Aidan Lynch was punished by former Lilywhite Anto Flood who raced onto the loose ball to fire to the net despite the best efforts of Ian Ryan to keep it out.
Three minutes later the home side thought they had equalised when Flanagan headed home a free-kick but the goal was promptly ruled out for pushing.
The Louth side’s evening then went from bad to worse on 64 minutes when midfielder David Cassidy was dismissed for a second bookable offence for protesting a decision with the assistant referee.
Jamie Duffy then had penalty appeals turned down for the home side moments later when he went down under a challenge from Greg O’Halloran in the area.
Shels then put the game to bed with seven minutes remaining when the in-form Flood cut in off the left wing to drill a shot past Chris Bennion to the far corner of the net.
Dundalk reached a new nadir when midfielder Paul Shiels was shown his marching orders for a second bookable offence three minutes later.
Dundalk: Bennion; Flanagan (Crowley, 73 mins), Lynch, Ryan, Crawley; Duffy, Shiels, Cassidy, O’Connor (Whelehan, 87 mins); Mulvenna, Farrell (Vaughan, 76 mins).
Shelbourne: Delaney; Chambers, Keely, Brennan, Hedderman; McGill, O’Brien (O’Halloran, 64 mins), Freeman, Keddy; Flood, Hughes (Murphy, 33 mins).
Referee: D Hancock (Dublin).