In the first match, Celta Vigo won 2–1, with Swedberg also scoring. The La Liga sixth-placed team won the two-legged tie 3–1 on aggregate.
Swedberg also scored against PAOK when the teams met in the league phase.
In total, the 22-year-old Swede has scored seven goals and two assists in 26 games this season.
Swedish centre-back Carl Starfelt also started for Celta Vigo and played the entire match.
Countryman Alexander Jeremejeff was substituted on for PAOK with ten minutes remaining.
