Ollie Horgan's side lost 1-0 to Cob Ramblers at St Colman's Park.
The games only goal was scored in the 31st minute by Robert Walters.
Harps did push for an equaliser in the second half but they couldn't force the final ball to square the game.
The game finished on an unsavoury note as the goal scorer Waters was sent off for a late tackle on Damien McNulty which resulted in both benches and players exchanging in a bit of pushing.
Speaking with Oisin Kelly on Sunday Sport, Manager Ollie Horgan was disappointed with the defeat.