Garry Fleming's goal saw off St Mirren 1-0, moving Dumbarton further clear of the Ladbrokes Championship relegation zone.The game's decisive moment came in the 50th minute when Fleming took a pass from Grant Gallagher, turned in the penalty area and shot powerfully left-footed into the top corner.The hosts had a second goal ruled out for offside, after Donald McCallum had beaten Buddies goalkeeper Jamie Langfield.St Mirren pressed for an equaliser but the Dumbarton defence held firm to record only their second home win of the campaign.The Sons' second successive victory moves them five points clear of their opponents and six clear of second-from-bottom Livingston.