Derry City remain third in the Premier Division after losing to Dundalk at Oriel Park on Thursday night.
Gareth McGlynn missed a 15th-minute penalty, Ruaidhri Higgins hit the bar and Eamon Zayed was denied by Peter Cherry before Paul Hawkins broke the deadlock with a header on 43 minutes.
Ger Doherty twice denied Mark Quigley in the first half.
Quigley hit the inside of the post early in the second half and Zayed shot wide in the final minute of the game.
McGlynn squandered a gilt-edged opportunity to give the Candystripes the lead when he was brought down by Michael Hector but Cherry saved his spot-kick.
Higgins' 25-yard snapshot cannonned off the woodwork in the first half and while Zayed was quickest to react he couldn't find the net.
Shamrock Rovers lead the table by two points from Sligo Rovers, with Derry City one of five teams who are a further point behind.