The victory in the semi-final comes a week after the team crushed Malmö 4–0 in the quarter-finals.
The reigning Swedish champions showed no signs of slowing down and last year's third-place finisher in the Allsvenskan, Gais, never came close to threatening.
Mjällby centre-back Tom Pettersson opened the scoring to make it 1–0. Elliot Stroud - who was named in the Swedish squad for the upcoming World Cup play-off - then extended the lead to 2–0 from a penalty. Jakob Bergström sealed the final score with his 3–0 goal.
Gais' current national team star Gustav Lundgren remained on the bench throughout the match. He has been suffering from a groin problem and has missed the last two cup matches.
In the final, Mjällby will face Hammarby.
