BOHEMIANS’ substitutes made the difference as Dundalk set a new benchmark.
The home side were poor in the first half but raised their game after the restart thanks in part to the introduction of Dayle Rooney, Declan McDaid and James Akintunde.
McDaid drew two good saves from Dundalk keeper George Shelvey and went close with a free-kick before the other two combined for the only goal of the game in the 80th minute.
Bohs won a free-kick on the right after James McManus was chopped down by Louie Annesley.
And Rooney delivered the perfect ball for Akintunde to head home for his third goal in six games.
It helped to ensure that Dundalk have suffered their worst start to a season in their history, failing to win any of their opening 10 games for the first time.
It leaves them rooted to the foot of the table with the sight of Robbie Mahon leaving on a stretcher another cause for concern.
But this win saw Bohs leapfrog Dublin rivals St Pat’s and Shamrock Rovers to draw level on points with second-placed Derry City, who have a superior goal difference.
Both sides were in action on Friday night but took a different approach to a second game in the space of 72 hours.
There were just five survivors from the Bohs team which had claimed an impressive win away to league leaders Shelbourne but Dundalk made just two changes to the side which had drawn with St Pat’s.
That might have been expected to tee up a contest between fresh energy and cohesion but if truth be told the first half was fairly manic with no great quality on show.
Bohs were playing into a strong wind but, even so, would have expected to created more opportunities than they did.
Making only his second start, Estonian international Martin Miller had a couple of bright moments for the home side.
He played in James Clarke who was unable to steer the ball past Shelvey and also drilled a low ball across the face of goal which Andy Boyle scrambled to clear.
But there was a lack of urgency overall with Miller withdrawn at half-time in favour of the more dynamic Rooney.
Dylan Connolly – Bohs captain for the night against his former club – did hit the back of the net but a free was awarded and Filip Piszczek booked for kicking the ball out of Shelvey’s hands.
The Lilywhites first threatened from a Daryl Horgan which Kacper Chorazka was unable to hold onto and they continued to cause Bohs problems in open play and dead-ball situations.
And they had the home side under the cosh as half-time approached with both Horgan and Robbie Benson hitting shots off-target.
They also had a penalty appeal turned down when Piszczek and Cian Byrne both failed to clear a corner. Benson fired over the bar but insisted he had been fouled by Paddy Kirk. They got a consolation corner.
But their best chance came on the stroke of half-time when Mahon got in behind Michael Lilander before drilling the ball towards the near post where Jamie Gullan was unable to get a telling touch under pressure from Bouba Keita.
Dundalk made their own change at the break with Anneseley introduced for Mayowa Animasahun who had been booked early on.
But it was Bohs’ subsequent changes which had the biggest impact with McDaid – who was introduced along with Akintunde – drawing two saves from Shelvey in quick succession.
First he cut in from the left and unleashed a shot which Shelvey palmed away with the ball eventually going out for a throw-in.
From that, Lilander crossed to the far post where McDaid was waiting but the ex-Nottingham Forest keeper was again equal to the effort, this time at the expense of a corner.
That set-piece did not yield anything but a later free-kick did with Bohs doing enough to see out the game.
SUN STAR MAN: Declan McDaid (Bohemians)
BOHEMIANS: Chorazka 7; Lilander 6, Byrne 6, Keita 7, Kirk 7; McDonnell 7 (B McManus 90, 3), J McManus 7; Connolly 6 (Akintunde 64, 7), Clarke 6 (McDaid 64, 7), Miller 6 (Rooney 46, 7); Piszczek 6 (Reinkort 81, ).
DUNDALK: Shelvey 7; Davies 6, Animasahun 6 (Annesley 46, 5), Boyle 6, Bradshaw 6; High 6, Doyle 6 (Keane 73, 5); Horgan 7, Benson 7 (Kenny 90, 3), Mahon 7 (O’Kane 60, 5); Gullan 6.
REFEREE: E O’Shea (Tipperary) 6