The home team now leads 3-2 in matches, best of seven, and can decide the series at home on Friday.
After a late equalizer, Karlskoga took the Hockey Allsvenskan semifinal against AIK to overtime.
It took another 41 minutes to score the decisive goal. 1:05 into the third overtime period, AIK's Lukas Zetterberg scored the winning goal.
It was incredibly nice. It was a tight match, with two incredibly good teams. I think we have good patience and grind it out, says Zetterberg to TV4 Play.
Halfway through the match, Karlskoga received a match penalty, as Johan Motin gave Scott Pooley a head tackle.
AIK took advantage of the five-minute power play and scored two goals, Christoffer Björk and Oscar Nord the goal scorers.
In the third period, Karlskoga reduced the lead through Hampus Plato. And with 2.5 minutes left, when goalkeeper Samuel Jonsson had left his net, Simen Andre Edvardsen equalized to 2-2 and took the match to overtime.
