Paul McMullan and Bilel Mohsni both struck in the first half to put the Tangerines on easy street and help them leapfrog rivals Morton into fourth place ahead of their return trip to take on Stephen Aitken’s Sons at Dumbarton this weekend.
The pitch survived an inspection just over an hour before kick-off after non-stop rain in Tayside during the day.
United had dropped into fifth place following Saturday’s 1-1 draw away to Morton so knew nothing less than victory would do.
Second-bottom Dumbarton arrived on the back of a hefty 3-0 defeat by Livingston at the weekend, and faced a home side determined to get their noses in front.
Sam Stanton tried his luck early on with a long-range effort which fizzed wide before McMullan’s darting run and shot meant Scott Gallacher was relieved to see it clear his far post. However, the hosts took the lead in style on the half-hour mark.
Scott McDonald’s precise pass was perfect for McMullan who wasted no time in sweeping his 12-yard shot past Gallacher and into the far corner.
Dumbarton, though, weren’t out of it. Two minutes before half-time, David Wilson found himself one-on-one with Harry Lewis only for the on-loan Southampton keeper to block with his legs.
Yet United increased their lead on the stroke of half-time. McMullan’s cross led to a scramble inside the box and defender Mohsni was on hand to prod home.
Lewis almost blundered at the start of the second half when he was robbed by Danny Handling, while at the other end McDonald’s rasping shot was fisted away by Gallacher.
Laszlo’s men could have added to their lead through Stanton and McMullan but the overwhelming feeling was one of relief.