Inverness Caledonian Thistle left the Marbill Coaches Stadium with three points thanks to a goal with the last kick of the game.
The visitors controlled proceedings in the opening 45 with Dumbarton having on-loan goalkeeper Milosz Sliwinski to thank for a couple of brave stops.
It was a different story after the break with Sons well on top throughout as Craig McGuffie rattled the bar and Joel Mumbongo couldn’t convert from close range.
It looked as if Dumbarton were going to put a well-earned point on the board but Alfie Bavidge popped up with a goal in the fourth minute of added time which turned out to be the last kick of the game.
Sons travel to Arbroath next weekend.