Substitute Mamudo Moro scored in added time to help Mjallby to beat Hammarby 2-0 on Monday night.
The 26-year-old was put through clear on goal and he struck it past goalkeeper David Ousted.
Moro, who was making his 25 league appearance, has now scored five goals.
He had come on his 74th minute to replace Amin Sarr.
Mjallby are 11th on the league table with 31 points from 26 matches.