Aberdeen fought back from a two-goal deficit to draw 2-2 with BK Häcken in Sweden.
The hosts led 1-0 at the break before an Ibrahim Sadiq penalty in the 69th minute doubled their lead.
But Aberdeen hit back through Bojan Miovski before Nicky Devlin scored his first Dons goal to level the scores with ten minutes remaining.
Debutant Jamie McGrath thought he had scored a late winner only for his effort to be ruled out. Häcken defender Johan Hammar received a late red card in the final minute.
The return leg at Pittodrie will take place on Thursday, August 31 – kick off 7.45pm.