The game was settled by the first serious effort either side had on target. Gavin Skelton made it to the by-line, and his low cut-back into a crowded area landed at the feet of James Grady, who swept the ball past Stephen Grindlay from eight yards.
Moments later it was almost two, but Grindlay brilliantly turned away Ryan McGuffie's deflected shot.
The introduction of John Gemmell to the Sons' rank early in the second half gave them an immediate threat, and when Gemmell sent Andy Rodgers clear through on goal he should have done better than fire weakly into the hands of a relieved Alan Main.
Gemmell grazed a post with a header and there were loud claims for a penalty when Rodgers' shot appeared to strike Derek Townsley's arm, but it was not to be Dumbarton's day.
Gretna should have made sure right at the death, but from a good position McGuffie was denied yet again by a flying Grindlay save.
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