Fridolina Rolfö started on the bench for Barcelona at home against Danish Køge but had to step in already after 23 minutes for the injured Mariona Caldentey.
Just six minutes later, the Swedish national team striker first reached on a post from the left and nodded in 2-0 to the home team.
The reigning champions Barcelona finally won 5-0 and thus went straight into the group stage with a crushing goal difference of 24-1.
In the last Champions League round, Rolfö stood for both goals and assists in the 4-0 victory away against Arsenal.
Arsenal, led by former Rosengård coach Jonas Eidevall, surprisingly fell to Hoffenheim (1-4) away in the last group game - but are still ready for the playoffs.
Hoffenheim scored a sensational three goals in the space of five minutes at the start of the second half and went up in a 4-1 lead.
It had taken two more goals for the Germans to snatch second place from Eidevall's gang.
The teams stayed on the same score but Arsenal went on by virtue of a better mutual goal difference thanks to a 4-0 victory in the home meeting.