The 28-year-old midfielder dispatched his second spot kick in the space of six days at the end of the opening period after Mick Leahy was adjudged to have fouled Brian Gartland from a corner.
The decision infuriated the visitors and their manager Dave Robertson, who felt the decision was soft especially as the Darren Meenan’s delivery had already been headed clear at the near post.
However, having already been given a warning minutes earlier by referee Ben Connolly for pulling the Dundalk centre half, Leahy should have known he was walking a tight rope.
Prior to that both sides had chances to open the deadlock with Kieran Sadlier going close with a 30 yard free kick for the visitors on the quarter hour mark before David McMillan blazed over from the edge of the area after racing onto Ciaran Kilduff’s knockdown on 25 minutes.
The Bit O Red did push for an equaliser on the restart and should have found it on 56 minutes when Liam Martin’s cross from the left found Jimmy Keohane but his shot across the face of goal flashed just wide.
The result puts Dundalk three points clear of Derry City, who travel to Longford Town tonight, with Sligo still awaiting their first victory of the new campaign.
Rogers; Gannon, Gartland, Boyle, Massey; Meenan (Mountney 75), Finn, O’Donnell, Horgan; Kilduff (Shields 58), McMillan.
Benson, Barrett, Poynton, M O’Connor, Sava.
Schlingermann; Adebayo-Rowling, Leahy, Boylan, Donelon; Sadlier, Keohane, Roddan, Russell (P Roberts 69), Martin; Cretaro (Gordon 87).
Lyons, J Roberts, Armstrong, Place, Nugent.
B Connolly (Dublin).