Galway United and Derry City also enjoyed wins
Dundalk have laid down a marker in the SSE Airtricity League Premier Division title hunt as they saw off the 10-men of Shamrock Rovers in Tallaght.
The reigning champions took the lead through a David Webster own goal on 15 minutes.
Things went from bad to worse for Rovers when captain Gary McCabe was sent off for a straight red card 15 minutes later for an over-the-ball tackle on Stephen O'Donnell.
Dundalk made sure of the points in the second half when Ronan Finn converted two minutes after the break with a low shot.
Referee Neil Doyle shows Shamrock Rovers' Gary McCabe a red card ©INPHO/Morgan Treacy
Dundalk stay top of the table.
Derry City remain two points behind the league leaders after the Candystripes were 1-0 winners over Bohemians.
Rory Patterson's 12th minute goal was enough for the home side to take all three points at the Brandywell.
Meanwhile, Cork City were 3-1 winners over Finn Harps at Turner's Cross with the game won in the first few minutes.
Derry's Rory Patterson celebrates his goal with teammates ©INPHO/Presseye/Lorcan Doherty
Early goals from Gearóid Morrissey and Sean Maguire put the Leesiders in charge before Kenny Browne's red card but Karl Sheppard's goal made sure of the points for the home side.
Ryan Curran notched the consolation goal for Finn Harps.
Two second half goals from Vinny Faherty gave Galway United a 2-0 win at Wexford Youths.