An outstanding Aberdeen display on one of those special European nights, back in front of the fans in full voice, put Stephen Glass' side firmly into the driving seat ahead of next week's second leg.
A new era began in bright sunshine at Pittodrie this evening, the start of Stephen Glass' first full campaign in charge with, at long last, the return of the advance guard of the Red Army to the old stadium. The manager gave Aberdeen debuts to new team captain Scott Brown, Christian Ramirez and Jay Emmanuel-Thomas from the off. New signings Teddy Jenks and Jack Gurr were on the bench, Declan Gallagher suspended for the game.
Brown set the tone from the off, chasing a lost cause the length of the field in the first minute, an early indication of the drive he is going to bring to the Dons. Häcken pressed in the fourth minute, Bengtsson intercepting a ball out from Brown and bearing down on goal, Jonny Hayes coming across to block the shot.
Considine collected the game's first yellow card on six minutes, blocking off a run by a Youssef and conceding a free-kick 20 yards out. Walemark's shot at goal was headed away by Emmanuel-Thomas in the wall. The Swedes had made a bright start, looking like a team a dozen games into their season with the sharpness that brings.
Aberdeen had their first look at the opposition goal on 15 minutes, Funso Ojo playing the ball across the top of the box to Ryan Hedges who laid the ball back to Lewis Ferguson, but his shot from 25 yards flashed over. Four minutes later, Calvin Ramsay's corner found Emmanuel-Thomas at the back post but at full stretch, he put his header over the bar as the Dons began to get into their stride.
Ferguson certainly found his range in the 25th minute, spearing a right foot drive at goal from 25 yards out, the ball flying beyond Abrahamsson only to smash against the foot of the post and bounce to safety.
Ojo was next to come close on 27 minutes, a Considine clearance finding Emmanuel-Thomas. He held the ball up well, then slid it into the path of Ojo, galloping forward at inside-left. Advancing on goal, the goalkeeper stood up well and saved at the near post. From the corner Emmanuel-Thomas headed the ball back across the face, Hedges and a defender getting a touch on it as it went behind for another corner.
That second corner did the trick though on 28 minutes. Ramsay's ball cross to the back post found Considine, who came driving on to the ball and deposited a powerful header into the back of the net, Considine celebrating goal 41 for the Dons every bit as passionately as any that had come before.
Aberdeen might have been two up on 31 minutes, Ojo first into the box, flicking the ball over the defender and into space but not quite able to get a convincing shot away. The ball found its way to Hayes on the left and his centre was met by a powerful Ramirez header, Abrahamsson juggling the ball before completing his save. Certainly the visitors were creaking now under an incessant Aberdeen assault.
Ferguson was on the chase forward on 38 minutes, bursting into space before chipping the ball forward for Hedges, but his header from 14 yards was well dealt with by the goalkeeper.
Ojo was again in with a chance on 40 minutes, Ferguson in behind and pulling the ball back across goal, Ojo not quite able to fetch the ball from just behind him as he darted in on goal.
Two minutes before the break, Hedges dashed into the box to latch onto a loose ball and as he won it, Bengtsson came across and chopped him down to concede a penalty. Despite Häcken delaying the kick, Ferguson was calmness itself, stepping up, sending the goalkeeper the wrong way and making it 2-0, fully deserved on the evidence of the first 45 minutes.
HALF-TIME: ABERDEEN 2 BK HÄCKEN 0
Häcken brought on Heintz at the break in place of Bengtsson as they looked to get back into the game. A couple of minutes into the half, Youssef took a knock in a challenge with Hayes and after extensive treatment, he was replaced by Maarouf.
By then, Ferguson had made it 3-0 with an absolute screamer in the 53rd minute, the Dons pressing high up the pitch, McCrorie winning the ball in the Häcken half and feeding Ferguson who advanced ten yards and simply bludgeoned a 25 yarder past Abrahamsson who barely moved.
The Swedes were dropping like flies now and almost immediately after the goal, Friberg was limping away, to be replaced by Faltsetas in the 55th minute. Häcken tried to rally and won a 58th minute corner but Hedges and Ojo combined to clear the ball to safety.
A minute later, the visitors were back in the game, Jeremejeff collecting the ball neatly, getting a slightly fortunate run of the ball before coming inside and curling a neat shot around Joe Lewis and just inside the far post. It was a reminder that this game - and certainly this tie - was far from over.
Aberdeen almost restored the three goal cushion on 63 minutes, hitting on the break. Emmanuel-Thomas held the ball up and then slotted Hedges in on the left, his fierce drive tipped over the bar by Abrahamsson. The Dons used their first substitute on 66 minutes, Jack MacKenzie replacing Ojo who had put in a real shift on his return to Pittodrie.
Ramirez almost opened his Aberdeen account on 69 minutes, chasing onto a through ball in the inside-left position, trying to lift the ball over the keeper with the outside of his right boot but putting it over the bar too.
Connor McLennan and Jack Gurr came on in the 77th minute for the Dons, replacing Hayes and Ramsay as Aberdeen brought some fresh legs onto the pitch. Häcken tried to seize the moment to put Aberdeen under pressure, winning another couple of corners in quick succession, the second causing chaos as it flashed across goal and, thankfully, to safety. The Swedes were sensing a second goal might be there for them as Walemark was replaced by Milovanovic in the 83rd minute, their fourth change.
His first act was to see Aberdeen make it 4-1. Great work from McLennan on the left gave him chance to pull the ball back for MacKenzie. He powered a shot in at goal, an effort that was blocked but fell perfectly for Ramirez to poke the ball into the net from a couple of yards out for a debut goal. Milovanovic showed his disappointment with a lunge on Ferguson a couple of minutes later, going into the book as a result.
Three minutes into added time, McLennan put some icing on the cake, scoring a superb fifth, collecting the ball on the edge of the box, turning inside and looping a vicious shot over the top of Abrahamsson and in.
On 96 minutes, Teddy Jenks got his Aberdeen debut, replacing Ramirez, the American striker getting a standing ovation as the game edged towards its close. On the final whistle, Brown led his ide around the ground to give the same kind of ovation to the fans as a euphoric Red Army prepared to make their way home - with plenty of optimism for the season ahead.