It was a grim night in Dundee for the Dons, gifting United two goals just before half-time and being unable to turn the tide after the interval.
With Jim Goodwin forced to watch from the stands, the return of Liam Scales in central defence was his only change to the Aberdeen side that beat Kilmarnock 4-1 last Saturday. Ross McCrorie moved into midfield and Matty Kennedy started from the bench. Among the subs was Connor Barron, back among the matchday 20 for the first time this season after injury. Leighton Clarkson was also back on the bench after his suspension.
After being beaten 2-1 at home by St Johnstone, Dundee United made four changes with Scott McMann, Craig Sibbald, Glenn Middleton and Tony Watt all starting, Ross Graham, Sadat Anaku and Ian Harkes dropping to the bench, Steven Fletcher absent altogether.
The hosts made a sharp start, Middleton rampaging down their left in the opening minute and with Jayden Richardson losing his footing, he was able to swing in a cross to the back post. McGrath got up highest, but put his header wide of the frame.
McGrath was trying his luck again in the fourth minute, robbing Ylber Ramadani outside the box before firing in a weak shot from 20 yards that was straight at Kelle Roos.
The Dons should have been ahead on 12 minutes. A deep ball from Vicente Besuijen found Richardson at the back post and he did well to hook the ball back across goal, with the goalkeeper nowhere. Bojan Miovski had what looked like a tap into an empty net from six yards but with the ball slightly behind him, rather than taking a touch, he tried to manufacture a backheel into the net but instead diverted it wide.
Marley Watkins bustled forward on 15 minutes, exchanged passes with Miovski just outside the area but pulled his left footed shot across goal and wide. A couple of minutes later, Miovski glanced a header wide from another deep cross from the left, this time from Hayden Coulson.
The Dons were on the break on 27, Roos hurling the ball out to Jonny Hayes who sprinted forward, skipped past a challenge but then overhit his cross with three Aberdeen men in the area.
McGrath was in the book on the half hour, hacking down Coulson as he darted towards the penalty area after good play between him, Hayes and Besuijen. Coulson needed treatment in the aftermath before continuing. The Dons were keeping the home side penned into their own half, but chances were few and far between.
A chance came at the other end on 41 minutes though and Behich tucked it away. Coulson was beaten to the by-line by McGrath who then cut the ball back into the path of Watt. His low shot was well saved by Roos but the rebound fell nicely for Behich to fire past him from close range for 1-0. Coulson was booked on 43 minutes as Aberdeen looked to recover.
Roos had to be off his line quickly as Watt chased down a long ball in the 45th minute. The goalkeeper cleared from just outside his area, but United picked up the loose ball. Freeman skipped past Coulson and Besuijen down their right to get to the by-line and again pulled it back to Watt. This time, there was no saving his shot as he smashed it just inside the post from ten yards out.
HALF-TIME: DUNDEE UNITED 2 ABERDEEN 0
Barron made his return for the Dons at the break, replacing Watkins as Aberdeen looked to repair the damage. United made a quick start to the half again, Levitt shaping a shot well wide on 47 minutes.
Hayes was on the charge three minutes later, crossing on the run, the ball just too far in front of Besuijen as he raced after it. On 52, Ramadani went down for treatment, having done likewise in the first half, but again he carried on afterwards. It was a disjointed opening for the Dons, United keeping the ball and keeping it in Aberdeen?s half of the field. It required a change and it came with Duk and Clarkson replacing Coulson and Besuijen on 57 minutes, Aberdeen switching to a back three.
It certainly started to turn the tide, Aberdeen on the front foot now, Clarkson sending two probing crosses through the box without finding any takers. He put through a third on 64 minutes, finding Miovski just inside the area. He chested the ball down but snatched at his shot and flashed it over the bar from 15 yards. This was better now from Aberdeen, United suddenly unable to get on the ball, Freeman booked for kicking the ball away.
How the Dons didn't score on 69 minutes, nobody knows. Clarkson put Miovski in again, his shot blocked. Miovski helped it back to Clarkson whose shot skewed across the box to Richardson. He took a touch, allowing the goalkeeper to swoop on it, though the deflection off him seemed to strike a United hand - no penalty. In the aftermath, Anaku Sadat replaced Middleton.
On 72, Collum did point to the spot - at the other end. Sibbald went round McCrorie and then hurled himself to the ground without getting a touch from the Aberdeen man, a questionable call from the referee. McGrath stepped up and stuck the penalty away for 3-0.
Watt was in behind ten minutes from time, but from a tight angle, Roos made a straightforward save at the near post, Sadat lashing the rebound into the crowd. Christian Ramirez and Shayden Morris replaced Ramadani and Richardson a minute later.
The Dons' day was summed up as McCrorie put the ball into his own net on 82 minutes. A long free-kick forward from United was going nowhere, McCrorie up to win the header and play it back, as he thought to his goalkeeper. Roos though had come out for the ball and could only watch as McCrorie's header drop into an empty net. Harkes came on for McGrath on 84 as the hosts ran the clock down. Three minutes later Graham and Pawlett replaced Behich and Watt.
Aberdeen continued to live dangerously, Stewart passing the ball across the area straight to Levitt but Roos was able to spare the skipper with a low save. Duk might have got a consolation on 92 minutes, up to win a header from Clarkson's cross, but it skidded off his forehead and wide. Story of the night.