Swedberg's 2-0 goal at the end of the first half was his third goal in five games in Europa League football. The midfielder also scored when the teams met last fall.
The former Hammarby player wasn't the only Swede to score in the match. The home team's Alexander Jeremejeff made it 2-1 in the second half.
The match was the first of two in the round of 32 between the teams. The return leg will be played in Spain in a week.
Corrected: In a previous version there was an incorrect statement about where the rebound was played.
