Match ends, Dundee United 1, Aberdeen 3.
Scott Vernon hit a superb hat-trick as Aberdeen saw off Dundee United in an enthralling meeting at Tannadice.
The 30-year-old broke the deadlock with an assured strike after Peter Pawlett's assist.
And, despite Sean Dillon levelling, Vernon put the result beyond doubt by sinking two further goals.
The Dons tightened their grip on second place in the Premiership, but United's hopes of securing European football through their league position are over.
This encounter comes with a long-standing history of great clashes, and it was evident from the off that this match would not disappoint.
Dundee United took to the pitch knowing only a win would do, as they looked to stay hot on the heels of Stuart McCall's Motherwell in third.
And they started with intent, but the away side gave as good as they got in the opening stages.
More than 100 goals have been scored in league games involving the Tangerines this season, and the packed crowd did not have to wait long to see one, as Scott Vernon - starting for the first time since January - gave the Dons the lead.
Following good work from Pawlett, Vernon confidently knocked a low shot beyond debutant goalkeeper Marc McCallum.
Despite going behind, the Scottish Cup finalists did not let their heads go down, and could have equalised through Nadir Ciftci.
The front-man did well to create an opening and test Jamie Langfield, but the experienced stopper was more than equal to it, pulling off an impressive save.
The pendulum then swung back in favour of the visitors, who were hungry to add to their lead, but both Vernon and Barry Robson were unable to take advantage of good opportunities.
Derek McInnes' men were made to rue those missed chances when United levelled through an unlikely source.
Dillon restored parity when he collected a Stuart Armstrong cutback and rifled a ferocious shot towards goal that, after a deflection off Mark Reynolds, sailed home.
That gave the hosts confidence, and it was only thanks to two magnificent saves from the resolute Langfield, first from an Andrew Robertson effort, and then Mark Wilson's volley that looked destined for its target before the keeper touched it on to the woodwork, that the sides were neck and neck at the break.
The second half carried on in the frenetic manner of the first, and Aberdeen thought they had got themselves in front again when Niall McGinn bundled home a header after McCallum spilled, only for the goal to be chalked off for offside.
The goalkeeper then blocked an effort from Vernon.
But, when Robson floated in a wicked corner, there was to be no denying the striker this time.
Rising to connect with the ex-Tannadice favourite's inch perfect back-post delivery, he nodded in his second.
United could have responded almost immediately when, after a fine team move, Ciftci found himself in space, only to send the ball blazing over.
Aberdeen were on the back foot as United looked determined to equalise, and Jackie McNamara's men will feel aggrieved not to have pegged things back again when Ryan Dow produced a neat finish, only for the assistant referee to make a dubious offside call.
And that frustration was a sign of things to come for the home team as, despite their efforts, it was the travelling support who were again on their feet when the troublesome Vernon capitalised on a defensive error from Gavin Gunning to bag his hat-trick and seal the win.
Vernon ghosted in behind the defender to round McCallum and roll the ball in, despite John Souttar's attempts to clear.
- 16WilsonSubstituted forEl Alaguiat 70'minutes
- 5GunningBooked at 90mins
- 18DowSubstituted forSmithat 86'minutes
- 29El Alagui
- 8FloodSubstituted forSmithat 31'minutes
- 15RobsonBooked at 21mins
- 9VernonSubstituted forZola-Makongoat 88'minutes
- 10McGinnSubstituted forTateat 74'minutes
- 11HayesBooked at 66mins
- Calum Murray
- Shots on Target
Second Half ends, Dundee United 1, Aberdeen 3.
Gavin Gunning (Dundee United) is shown the yellow card.
Foul by Gavin Gunning (Dundee United).
Calvin Zola (Aberdeen) wins a free kick in the defensive half.
Morgaro Gomis (Dundee United) wins a free kick on the right wing.
Foul by Peter Pawlett (Aberdeen).
Substitution, Aberdeen. Calvin Zola replaces Scott Vernon.
Attempt missed. Brian Graham (Dundee United) header from the centre of the box misses to the right.
Corner, Dundee United. Conceded by Jamie Langfield.
Substitution, Dundee United. Scott Smith replaces Ryan Dow.
Foul by Brian Graham (Dundee United).
Russell Anderson (Aberdeen) wins a free kick in the defensive half.
Goal! Dundee United 1, Aberdeen 3. Scott Vernon (Aberdeen) right footed shot from the centre of the box to the centre of the goal. Assisted by Jamie Langfield.
Foul by Farid El Alagui (Dundee United).
Barry Robson (Aberdeen) wins a free kick in the attacking half.
Substitution, Aberdeen. Alan Tate replaces Niall McGinn.
Corner, Dundee United. Conceded by Cameron Smith.
Attempt missed. Niall McGinn (Aberdeen) right footed shot from a difficult angle and long range on the left misses to the left.
Attempt saved. Brian Graham (Dundee United) right footed shot from the centre of the box is saved in the centre of the goal.