Ericsson fired home from the edge of the area to give 11th-placed Haecken the lead in 35th minute and Lewicki doubled the home side's lead with a bullet header 10 minutes after halftime before being sent off for a bad tackle.
Malmo went into the game knowing that nearest rivals IFK Gothenburg had lost 2-1 away to Djurgarden but failed to capitalise.
Malmo top the table on 54 points with three games to go, four points ahead of IFK Gothenburg.
Helsingborg hammered Halmstad 4-2 to move into third place on 49 points, one place ahead of AIK who beat Mjallby 3-2 on Friday night, on goal difference.
- Sports & Recreation
- IFK Gothenburg