After the 0-1 loss in Brussels last week, most people probably did not believe in the Allsvenskan team before Thursday's return meeting.
Häcken, on the other hand, got a dream start when Adrian Svanbäck gave the home team the lead in the 33rd minute and the meeting was tied overall.
Danish national team striker Kasper Dolberg, who decided last time, equalized to 1-1 on a penalty in the 54th minute and gave Anderlecht a new advantage.
Augustinsson missed
The Belgian top team went for advancement, but Häcken got a penalty in extra time in the second half after a VAR review. Team captain Simon Gustafson shot the match to extra time in the 92nd minute with his 2-1 goal.
The extra time remained goalless and the meeting had to be decided with a penalty shootout. There, Swedish national team defender Ludwig Augustinsson missed his penalty for Anderlecht at the same time as Häcken's goalkeeper Etrit Berisha saved another and scored the decisive one.
"Enjoying immensely"
He is enormous in penalty shootouts. I do not know what more I should say. It becomes kind of superfluous, says Simon Gustafson in Aftonbladet's live broadcast.
I like when it's that kind of match. I live for that kind of match. I enjoy immensely, says Etrit Berisha.
Häcken will now meet Brann in the third round of qualifying for the European League. The Norwegian team was knocked out of the Champions League qualifying on Wednesday in the meeting with RB Salzburg in the second round of the tournament.
For Anderlecht, play in the qualifying for the European Conference League awaits in August.