It was a game in which the Terrors should have sealed in a blistering opening 20 minutes.
But it was a game which was transformed in the second half and Jimmy Calderwood's men will have counted themselves unlucky not to have left with a share of the spoils.
It had been a disastrous opening for the Dons after losing the first goal after only eight minutes.
Following sustained pressure from the Tangerines with two early chances for Warren Feeney, Franciso Sandaza continued his goalscoring form courtesy of a terrible error of judgement from Scott Severin.
A deep ball from Sean Dillon appeared to be running out over the bye-line but Morgaro Gomis nicked the ball as the defender ushered it out for the Spaniard to run in and toe poke it past Jamie Langfield from three yards.
It was 2-0 five minutes later with another present from the Aberdeen defence.
Paul Dixon fought with Jared Hodgkiss on the left flank and powered through to cross low from the bye-line.
A hesitant Langfied left the ball along with a couple of defenders giving Feeney an easy first goal for United.
With a change in personnel and formation in the second period, the visitors dominated the play pressing forward against a United side which surprising slipped deeper and deeper.
It was no surprise that the Dons pulled a goal back in the 67th minute.
Sone Aluko whipped in a deep cross and Luksaz Zaluska was indecisive which allowed Lee Miller time to head the ball back into play for Darren Mackie to out-jump a static United defence and head in.
The away fans roared and Aberedeen fought like tigers for every ball, but United should have wrapped it up in the 75th minute when man of the match Scott Robertson hassled ex-United man Mark Kerr.
United had three men against Langfield but, instead of passing, Sandaza pushed the ball past the post much to the fury of his fellow players.