Four points from their previous two games had taken Jaro within two points of SJK, who made the short trip from Seinajoki deperately looking to end a two-game losing run.
That run looked set to continue with just over half an hour gone, when Jaakko Moisio blocked a cross with his hand, allowing Herman Sjogrell to score his fourth goal in as many games, putting his penalty just out of Roope Paunio's reach.
But five minutes into the second half, SJK drew level thanks to a superb goal from Kelwin Souza, who collected Armaan Wilson's pass with his back to goal, shrugged off his marker, beat another defender and curled a wonderful low strike into the bottom corner from 25 yards.
However, the evening belonged to the home side, who scored the winner soon after the hour mark, when Rudi Viktrom's though pass found Kaius Harden in acres of space on the left side of the area, and he made no mistake with his finish.
Jaro knock SJK out of 10th place, moving a point clear, though both sides are likely to face each other again in the relegation group, as they are 10 and 11 points off the top half with five games to play.