Goals from Ross McCrorie and Ryan Hedges earned Aberdeen a third qualifying round trip to Lisbon to face Sporting Club de Portugual thanks to a 2-0 win at Viking FK.
The Norwegians pushed the Dons all the way but the Dons’ bigger goal threat proved the difference on the night in Stavanger.
Dons boss Derek McInnes made one change to the team which beat Kilmarnock on Saturday with Matty Kennedy missing out due to injury. His place was taken by Dylan McGeouch.
The Dons tested Viking goalkeeper Iven Austbo twice in the opening eight minutes as they pushed for an opener.
Marley Watkins saw his header from a Jonny Hayes cross tipped over the crossbar by the home goalkeeper before Austbo held a 20 yard drive from Ross McCrorie.
But the best chance of a bright opening from the Dons fell to Scott Wright who was sent clear on goal by Ryan Hedges but the attacker saw his effort blocked by the home goalkeeper.
Having failed to take one of those chances Viking grew in confidence and the home side had two chances of their own to open the scoring. Both fell to Ylldren Ibrahimaj but he failed to hit the target with either effort.
The chances seemed to knock Aberdeen’s confidence and Viking took control of the game but it was the visitors who made the breakthrough in the final minute of the first half.
A Dons corner found Scott Wright on the edge of the box and his shot was blocked by a Viking defender but the ball fell to McCrorie who fired home his second goal for the club to give Aberdeen the lead.
There was much debate among the officials about whether Andy Considine, who had been in an offside position, had blocked the goalkeeper’s view of McCrorie’s goal but eventually the goal was given.
Chances were at a premium in the second half but Joe Lewis was called into action 18 minutes from time to save a Veton Berisha shot but Ryan Hedges secured Aberdeen’s passage to the third round 12 minutes from time when he scored direct from a corner to double his side’s lead.