Dumbarton slipped into the bottom two of the Ladbrokes Championship with a 2-1 home defeat by Morton.The visitors' goals came from Joe McKee and Denny Johnstone.Morton opened the scoring after 40 minutes when McKee netted from a corner. Dumbarton were back in the game with 52 minutes on the clock when Darren Barr levelled things up with a shot into the top corner.But Johnstone was in the right place to secure the victory for Livingston when he scored with five minutes remaining to leave Morton sitting in sixth in the division and well-placed to challenge for a place in the play-offs.