Dundee fell back to the bottom of the Premiership as they got a bit of a pasting at Pittodrie.
There is no doubt this Dark Blues side has improved under new boss Jim McIntyre but the Dens players took the night off in Aberdeen.
They paid the price for a dire display by dropping below St Mirren on goal difference, with minus 26 to the Buddies’ minus 23.
It was also hardly ideal preparation for Saturday’s trip to Celtic Park.
Dundee were up against it from kick-off and let themselves down with some dreadful defending.
Sam Cosgrove had the Dons two up by the break, his first goal a header on 16 minutes and the second a low strike just before the interval.
Andrew Considine scored the third just after the break then Connor McLennan volleyed in the fourth.
Calvin Miller got a consolation for the visitors before Considine made it 5-1.
The Dens men made a couple of changes to the line-up that started the match at Kilmarnock.
Nathan Ralph was back in at left-back after suspension, with Andy Boyle dropping to the bench.
In midfield, there was no Glen Kamara, with the Finnish international named as a sub. Lewis Spence took his spot.
The history of the fixture was against Dundee, with the Dark Blues having lost on their previous five visits to Pittodrie and not won in 11 games at the Dons’ stadium since a 2-1 success in May 2004.
Slack play by Dundee out on the right opened up the wing for home captain Graeme Shinnie to send over a low cross that was turned behind by defender Cammy Kerr. Dundee then had their skipper Kenny Miller to thank at the resultant corner as the striker booted Stevie’s May’s strike off the line.
The Dons continued to attack and, when they won a freekick 30 yards out on 11 minutes, Dundee goalie Jack Hamilton had to get down to save Lewis Ferguson’s shot.
Aberdeen were knocking at the door and it opened on 16 minutes.
Kerr did well to block a May drive but the ball was recovered by the hosts out on the right. McLennan ran on and swung a beautiful cross that was headed into the net from a couple of yards out by Cosgrove.
It was notable that, when the ball hit he back of the net, Dundee central defender Genseric Kusunga was lying in the Aberdeen box injured. The Dens men, therefore, were forced into making a substitution, with Boyle coming on for Kusunga.
Hamilton was called into action again on 20 minutes when he did well to hold another Ferguson shot.
Niall McGinn’s corner for Aberdeen on 28 minutes caused havoc by staying in play when most people – Hamilton included – thought it was going out. Ferguson headed back across goal but, fortunately for the Dark Blues, the danger was cleared.
Four minutes later, Jesse Curran showed Dundee were still full of belief when he nutmegged Max Lowe then sent a low ball into the six-yard box in the direction of Calvin Miller, who just couldn’t reach it. Any kind of touch and it was a goal.
Hamilton was being kept busy and he pulled out a fine save to keep out Shinnie’s shot on the turn on 36 minutes.
Play opened up for Dundee’s Ralph just before on 43 minutes and he raced on before firing in a drive that was held by Lewis.
The Dons then went up the pitch a minute later and made it 2-0.
They broke with speed and precision and it was Cosgrove who was the hero again on 44 minutes.
The striker won a header then was played in down the right by a return pass from the impressive Ferguson. Cosgrove ran on unchallenged before slamming his shot right between Hamilton’s legs and into the empty net.
It was the last thing the 337 away fans wanted to see just before half-time.
Dundee waited just four minutes of the second half before bringing on Kamara for Spence. The substitution was made right before a corner, from which the Dons made it 3-0.
It was a defensive disaster for the Dark Blues, who had two players lying on the deck as the unmarked Considine nodded McGinn’s corner past Hamilton on 50 minutes.
The proverbial roof caved in on the Dens men six minutes later when McLennan slammed a 12-yard volley into the net.
It should not have been allowed, though, because McGinn was offside and was duly flagged by the linesman. Referee Nick Walsh kept play going, though, and May fed the ball to McGinn, who delivered the ammunition for McLennan. Dundee’s Martin Woods was booked for protesting and he had a point.
Miller got one back for the visitors on 68 minutes but it wasn’t Kenny, who had been replaced by Benjamin Kallman by then.
Instead, the consolation strike went to Calvin, whose crisp strike from outside box deserved to matter more than it did.
Considine, though, grabbed Aberdeen’s fifth with another header on 72 minutes.
There was an injury scare for Dundee 10 minutes from time when Darren O’Dea needed treatment to a thigh injury but he played on.
With the game well over by then, the Dons strolled to the full-time whistle.
Aberdeen: Lewis, Logan, Lowe, Considine, McKenna, Shinnie, Ferguson, McGinn (Wilson 78), May (Ball 62), Cosgrove (Forrester 77), McLennan. Subs not used: Cerny, Gleeson, Wright, Anderson.
Dundee: Hamilton, Kerr, Ralph, Woods, Kusunga (Boyle 17), O’Dea, C. Miller, McGowan, K. Miller (Kallman 61). Curran, Spence (Kamara 50). Subs not used: Parish, Nabi, Inniss, Moore.
Referee: Nick Walsh.