Following the 5-1 demolition of BK Häcken in the first leg, it was perhaps unsurprising that Stephen Glass named an unchanged starting XI as the Dons looked to finish the job in Gothenburg. Declan Gallagher had his first involvement with the club as one of the substitutes, Tom Ritchie also coming onto the bench as a third goalkeeper. Dean Campbell missed the trip with a minor groin injury.
In contrast, the hosts made five changes to their starting XI as they headed off in search of the big victory they needed to turn the tie around. Out went Sverisson, Walemark, Toivio, Friberg and Youssef to be replaced by Carlsson, Olsson, Faltsetas, Heintz and Traore.
Häcken made the swift start they needed and within the first minute, Bengtsson and Traore had both had shots at goal charged down just inside the Aberdeen box.
Sharp work from Heintz put himself into good space in the fifth minute and he shaped a shot around Joe Lewis but against the outside edge of the post from 14 yards out as the Swedes posed some early problems.
Nine minutes in and Jay Emmanuel-Thomas launched a drive at goal from 30 yards out, the ball stinging Abrahamsson's palms as Aberdeen offered their first threat. Much like the game at Pittodrie, after a slightly torrid opening phase, the Dons began to exert better control of the game as we reached the quarter of an hour mark.
Christian Ramirez had a good chance on 20 minute, Emmanuel-Thomas and Funso Ojo combining well down the left to pull the ball back to Ramirez on the edge of the six-yard box, but he missed his kick as he tried to pivot on the ball.
More good play from the Dons almost earned a goal on 27 minutes. Scott Brown did well mopping up in midfield, winning the ball high up and interchanging passes with Emmanuel-Thomas before feeding Ryan Hedges. He cut into the box and found Emmanuel-Thomas again. He picked his way delicately past a couple of challenges before poking the ball at goal, Abrahamsson making a fine save to keep him out as the rain came teeming down. Does it always rain in Gothenburg?
Häcken heads were starting to drop as the scale of the job was getting bigger and bigger by the moment, Aberdeen having come through a tricky start to begin exerting real authority on the game. They might have had their first goal on 33 minutes, Ross McCrorie doing well to bring the ball out and find Emmanuel-Thomas. He slid a beautiful reverse ball in behind only for the goalkeeper to deny Ramirez as he chased onto it.
On 40 minutes, Mohammed was introduced to the fray by the home side, replacing the injured Jeremejeff as the hosts tried to find some way back into the tie, though that was looking a pretty forlorn hope for them by now as they began to look a beleaguered bunch.
Lewis Ferguson almost found a goal in added time, a lovely curling header from Jonny Hayes' free-kick bound for the top corner before Abrahamsson clawed it away. From the resulting corner, the goalkeeper was less convincing as he fumbled a weak volley from Emmanuel-Thomas. At the break though, it was a very pleasing first 45 minutes for the Dons.
Walemark came on for Häcken at the break, replacing Traore. Twelve seconds into the second half, Emmanuel-Thomas was on the ground needing treatment after a clash of heads with Carlsson, before being replaced by Teddy Jenks on 50 minutes.
As the Dons were reorganising, they lost the ball 25 yards out to Olsson who played a quick one-two with Heintz on the edge of the box before slotting the ball across Lewis and just inside the far post before scampering after the ball and screaming at the crowd to get behind his side.
Hayes went in the book on 54 minutes, a poor decision as he tried to pull away from contact with Walemark who flew into the air as he saw the Irishman coming.
The Dons really should have equalised and killed the tie stone dead on 55 minutes, breaking swiftly from a Häcken corner, Jenks setting Ramirez away down the right. His cross was perfectly judged for Ojo running onto it but somehow, he failed to make contact with the goal gaping.
Lewis kept it at 1-0 with a brilliant save to his left on 59 minutes, Ekpolo having set up Mohammed 15 yards out, but the Aberdeen goalkeeper was equal to the task, tipping it round the post with a strong left hand. In the aftermath, Stephen Glass collected a yellow card from the referee.
Jack MacKenzie and Connor McLennan were the next substitutions for Aberdeen on 66 minutes, Ojo and Hayes replaced. Within a minute though, the Dons were in trouble, Bengtsson played through and clipped by Lewis, going down for the penalty, Lewis yellow carded. Bengtsson stepped up to take the spot kick, sent Lewis the wrong way and gave Häcken a sniff of a chance.
Walemark, who should have been booked five minutes earlier, finally got his yellow card on 70 minutes for a hack on MacKenzie, Hedges also booked in the aftermath. Walemark had completely lost his discipline by now and moments later, he lashed out with an elbow at MacKenzie and collected his second yellow card. Häcken coach Høgmo was booked for his protests, but it was a moment of real madness from Walemark with his team beginning to threaten.
Having got back into the tie, the home side were doing their best to toss it away again as Mohammed then went through Ferguson late and was booked too as the game went through a crazy few minutes. It got stranger still when Gallagher was booked while warming up on 76 minutes. Sverisson then replaced Olsson.
Ramsay was next into the book on 79 minutes, presumably for time wasting as he tried to take a corner. It was the final throw of the dice for Häcken on 80 minutes Maarouf and Milovanovic replacing Heintz and Berggren as the game degenerated into one stoppage after another. There was another two minutes later when Jack Gurr and Gallagher replaced Ramsay and Hedges.
We were back to the football on 87 minutes, Ferguson whipping a free-kick round the wall from 25 yards out, Abrahamsson flying across goal to tip the ball wide. The Dons were close again a minute later, MacKenzie's deep free-kick reaching Ramirez at the back post. He flashed the ball through the six yard box, Considine inches away from getting the finishing touch.
Maarouf added his name to the referee's report in added time as the hosts' frustration built and the Dons edged towards the next round. Gurr had a sight of goal on 93 minutes, Abrahamsson pushing the ball to safety and protecting his clean sheet after his torrid evening the previous Thursday.
With that, the Dons were through a feisty evening and on their way to some more European nights.