It was in the eleventh minute that Amanda Persson got the ball on the left wing.
She was going to hit a cross into the penalty area, but it was a bit of an oblique kick and instead it sailed all the way over goalkeeper Lovisa Koss.
- It wasn't really a shot, but it worked, so maybe I should continue like that, says Persson.
Left winger Persson continued to impress in the first half and she was also the one who hit the corner that Slovakian Patricia Fischerova headed in to make it 2-0.
In the 67th minute, Kalmar received a penalty after Violah Kambi fell in the penalty area.
The BP players protested loudly, but it was of little help as Juliette Kemppi then fired the penalty into the crossbar.
BP reduced to 3-1 Mathilda Johansson's brilliance and in extra time centre-back Vaila Barsley scored.
The match was a real thriller, but Kalmar persevered.
After today's results, BP is fighting with Umeå and AIK over which teams will go straight out of the women's league and which will qualify.
The victory means that IFK Kalmar has five points down to just BP, who are in the qualifying spot.
At the same time as Kalmar won, league champions AIK also lost 5-0 away to Vittsjö.