Struggling Dumbarton took another giant step towards safety as they followed up last weekend's victory at league leaders Brechin City with a stunning victory over another of the promotion hopefuls. Morton, however, will be left to rue their inability to take chances or defend set-pieces as these cost them the points in a game they dominated for long periods.
The visitors swarmed towards the home goal from the start, but Sons' keeper Stephen Grindlay was never seriously tested until he had to leap to turn over Scott Bannerman's speculative 50-yard effort in the 23rd minute.
His opposite number, David McGurn, had been a virtual spectator but he was helpless moments later when Sons' skipper Paul Ronald collected a throw-in on the edge of the box and sent a shot screaming into the top right-hand corner of the net.
Grindlay's legs then denied Chris Templeman after the big striker had held off Robert Walker's challenge, but it was Dumbarton who added a second when Morton failed to clear a corner and Iain Russell prodded the ball over the line.
Encouraged, no doubt, by Jim McInally's half-time team talk, Morton threw everything at the packed Sons' defence which held firm. Only a Peter Weatherson free-kick which flashed over causing any serious worry.
The points were wrapped up for Dumbarton courtesy of some more poor defending. Russell was left totally unmarked six yards from goal and he had the easiest of tasks to guide James Allan's free-kick past McGurn.