Aberdeen came from behind to win a pulsating north-east derby thanks to Peter Pawlett's stoppage-time header.
John Souttar had put Dundee United ahead when Jamie Langfield missed Mark Wilson's corner and the Aberdonian easily blasted the ball into the net.
Former United captain Barry Robson fired the Dons level from the penalty spot after Andrew Robertson handled.
Radoslaw Cierzniak produced a string of saves but was helpless as Pawlett finally headed home a late winner.
A full house at Tannadice created an electric atmosphere and an opening half played at a frantic pace, with Aberdeen dominating possession in the first quarter but failing to create real chances.
Torrential rain made underfoot conditions difficult and it was the 30th minute before the first clear-cut chance was created.
United defender Souttar dallied 30 yards from goal, Pawlett dispossessed him, raced forward and unleashed a shot from the edge of penalty area.
But Cierznak stood up to beat the shot clear for a corner.
Souttar was caught out again 10 minutes later, losing the ball to Scott Vernon on the left side of play, but the striker was penalised for his challenge to win the ball from goalkeeper Cierznak who had raced to clear.
Vernon then tumbled outside the box after a great Aberdeen break and another chance was gone.
United, though, were coming more and more into the game and won a corner after a fierce Robertson drive was deflected behind.
The home side took the lead five minutes after the restart, Souttar blasting a loose ball home from four yards from a corner on the left.
Just before that, Pawlett had brought a fine save from Cierznak, blasting a ferocious drive at the United goal after a corner had not been dealt with.
Aberdeen levelled in 65 minutes from the spot after Robertson was judged to have used an arm to control the ball and Robson blasted home the equaliser.
Niall McGinn then brought a spectacular save from Cierznak, who shortly afterwards made another good low stop from Pawlett's shot.
It was Pawlett, though, who struck the decisive blow in the last minute of official time, heading home from two yards after Cierznak had parried a deflected header into his path.
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