It was happy new season for United as they posted their first win at Pittodrie since October 2009 in style.
First half goals from Ryan Dow and Gary Mackay-Steven earned Jackie McNamara’s men a two goal interval advantage.
And although Aberdeen pressed hard, particularly in the latter stages, United remained resolute.
A third goal from Chris Erskine in stoppage time sent the 2016 already celebrating Arabs home ready to party.