A dramatic goal from substitute Josh Thomas, four minutes from time, gave Drogheda United a third consecutive 1-0 league win over Alan Reynolds' side as the visitors took the spoils after a month without a league game.
Just when it looked like the game was heading for a draw, Drogheda won it as a sumptuous through ball by Conor Keeley straight down the middle picked out Thomas in the 86th minute who then outstripped the home defence and coolly put the ball past Kacper Chorazka.
Drogheda had only played a single match in the last month before the visit to Dalymount, disposing of Crumlin United in the FAI Cup, having lost out in a place in the UEFA Conference league due to a club ownership conflict.
Drogheda had been kicking their heels as a result and had a mid-season training camp in Spain to keep their players ticking over.
However, they came back to action with a late smash and grab to severely dent Bohemians' title ambitions, as they remain seven points behind leaders Shamrock Rovers and now having played a game more than the Hoops who can go 10 points clear if they beat Derry City on Sunday evening.
Crunching tackles and fouls littered the opening period as second faced fourth with Bohs four points ahead of the visitors prior to kick-off, but there were chances.
Straight from the kick-off Drogheda lost possession and Dayle Rooney, inside his own half, spotted United keeper Luke Dennison off his line and his audacious effort didn't miss by much.
Moments later Bohs right-back Ross Tierney was caught in possession by Dare Kareem, but Kacper Chorazka saved Kareem's effort on the edge of his six-yard box.
Kareem was brought into the club in the off-season as an Under-20s player but injures, and the departure of Douglas James-Taylor to Bohemians, has seen the 19-year-old elevated to the senior squad.
On the quarter hour, a ball from Bohs captain Dawson Devoy outfoxed the visitors defence and picked out Tierney all alone in the area. He looked certain to score only for Dennison to pull off a brilliant point-blank save with his leg to keep the game scoreless.
A poor headed clearance from Conor Kane then fell for Drogheda centre-half Conor Keeley who turned and shot from the edge of the area, with his dipping effort just clearing the Bohs crossbar.
The helter-skelter nature of the game continued after the break as both sides looked for the breakthrough goal, but a combination of poor finishing and last-ditch tackles kept the game scoreless.
Jordan Flores’ shot from the edge of the area came though a ruck of players and Dennison did well to get down late to save just after the hour mark.
On 73 minutes, Connor Parsons delivered a cross to pick out Tierney at the back post who smashed his shot into the side netting, with many of the home support thinking it had hit the back of the net, which garnered much derision from the away supporters.
Just when the game appeared to be heading for a scoreless draw, Thomas was the coolest player on the pitch, taking his time when one on one with the keeper to slot home the cheekiest of winners for Drogheda with 86 minutes on the clock.
Bohemian FC: Kacper Chorazka; Niall Morahan, Cian Byrne (Keith Buckley 71), Rob Cornwall (Markuss Strods 90), Jordan Flores; Connor Parsons (Rhys Brennan 81), Dawson Devoy, Ross Tierney, Dayle Rooney; Colm Whelan (Adam McDonnell 81), James Clarke.
Drogheda United: Luke Dennison; Andrew Quinn, Conor Keely, James Bolger (John O’Sullivan 87); Owen Lambe, Luke Heaney (Shane Farrell 77), Ryan Brennan (George Cooper 87), Daragh Markey, Conor Kane; Dare Kareem (Joshua Thomas 63), Thomas Oluwa (Warren Davis 63).
Referee: Paul Norton
