It was a game which the Tangerines could have and should have won, but also one which would have still given Dons manager Jimmy Calderwood hope that his troops are still in the hunt for that elusive spot.
After being totally out-played in the first period, the Dons stormed back into the game in the second half with an aerial threat which United found hard to contain.
But their gameplan fell apart in the 75th minute when ex-United man Mark Kerr completely lost the plot following his foul on Craig Conway and was shown a red card for his dissent towards the official.
This had followed a pulsating first half in which the United fans were left feeling somewhat relieved at the break after seeing their team completely dominate play and yet go behind in the 33rd minute to a Lee Miller piece of magic.
The striker, returning to a cauldron of hate at Tananadice, was fortunate to be on the park as in the 24th minute he had clearly punched Darren Dods in a tussle yet, astonishingly, the ref had only given him a yellow card.
The Terrors had felt aggrieved as they had been in the ascendancy from the kick-off with David Goodwillie signalling their intentions as early as the first minute with an 18-yard strike which skimmed over the bar.
Playing with fluency and skill, the hosts created a number of chances and yet it was the Dons who grabbed the lead with their first corner.
Charlie Mulgrew's deep inswinger was headed back across goal by Scott Severin for the unmarked Miller to wheel and hit the net with an overhead kick.
But the lead only lasted six minutes as United pulled back a superb equaliser.
A long cross-field ball from Prince Bauben found David Robertson who crossed from the byline for Goodwillie to head high into the net from six yards out.
With a reorganised side, Aberdeen pushed forward in the second period but after Kerr's departure, they were fortunate not to go behind as Craig Conway's thunderous free-kick rattled off the inside of the post.
But they held out as United cursed a missed opportunity to go level with Hearts.