Forced into this semi-final replay by Derry City, Stephen Kenny’s side were forced to battle throughout the 90 minutes as the home side’s endeavour and tenacity fell short on the night.
In a close encounter, Derry will be bitterly disappointed but their hopes of a place in next season’s Europa League remain on track, a target which had been identified at the start of the season.
Dundalk made five changes from the team which started Sunday’s game with experienced defenders Sean Gannon, and Brian Gartland on from the start.
Midfielders Darren Meenan, Ronan Finn, and Robbie Benson were also included from the first whistle with Derry boss Kenny Shiels opting for three changes — Harry Monaghan, Ben Doherty, and Ronan Curtis were all in the starting XI.
For Shiels, the inclusion of Curtis, who netted that 84th-minute equaliser at Oriel Park last weekend, proved particularly positive, the winger breaking the deadlock after just three minutes.
Monaghan outmuscled Dundalk centre-back Patrick Barrett when in possession and as the ball broke to Barry McNamee, his low cross into the six-yard area was driven home by the advancing Curtis.
That goal saw the Brandywell attendance of 3,000 — Derry’s biggest crowd of the season — erupt.
Clearly stunned by Derry’s early strike, Dundalk did manage to settle and a slick move in the ninth minute could have been rewarded.
Chris Shields dispossessed Aaron McEneff and when the ball had been worked forward into the danger area by Sean Gannon, John Mountney ballooned it high over the crossbar when he really should have done better.
Brian Gartland got his head to a Mountney corner in the 13th minute but failed to hit the target when under pressure from Rory Patterson.
Having enjoyed lengthy spells of possession, Dundalk were rewarded for their efforts when awarded a penalty in the 36th minute.
Derry centre-back Niclas Vemmelund appeared to impede Robbie Benson inside the danger area and referee Dave McKeon immediately pointed to the spot.
Dundalk’s loan hitman, Ciaran Kilduff, took possession of the ball before casually placing it to the left of Derry goalkeeper Ger Doherty. The Lilywhites were back in the game.
The home lot refused to be intimidated though and McEneff was unlucky when his powerful free-kick from 35 yards was deflected wide of the target for a corner in the 39th minute.
The Derry scorer almost repeated his early scoring antics after the break, Curtis gaining possession on the right flank, but his shot was blocked by the legs of a well-placed Dundalk defender just seconds after the restart.
Playing down the hill, the home side continued to enjoy a bright start and an unfortunate slip at the vital moment in the 52nd minute put paid to Patterson’s effort from 16 yards.
Derry threatened again in the 67th minute when Gartland squandered possession but McEneff’s low shot was well saved by Gabriel Sava.
However, one minute later, Dundalk moved into the driving seat. A cross from Darren Meenan was met by the head of Ronan Finn who glanced the ball just inside Doherty’s far upright.
Patterson had another goal-bound shot blocked by Sean Gannon in the 76th minute as the home side heaped the pressure on.
The introduction of defender Andy Boyle at the expense of Darren Meenan confirmed Dundalk’s tactics near the end, the Lilywhites now preparing to face Cork City in the decider in the Aviva Stadium on November 6.
G. Doherty; McDermott, Vemmelund, Jarvis; Monaghan (Schubert, 89), McEneff, McCormack, Curtis, B. Doherty (Boyle, 82;, McNamee; Patterson.
Sava; Gannon, Gartland, Barrett, Grimes; Mountney, Shields, Finn; Meenan (Boyle, 74); Benson (Horgan, h/t); Kilduff (McMillan, 63).
D. McKeon (Dublin).