Orgryte were looking up the table for the first time in a while after taking four points from their previous two matches, though a tough trip was in store to a Vasteras team who had taken seven from their previous three, only being held by champions Mjallby.
And the home side were on their way to continuing their fine run in the 13th minute, as Mikkel Ladefoged shrugged off his marker before directing a header on goal, which was well saved by Hampus Gustafsson, but following up instantly was Axel Taonsa to turn it home.
Ladefoged and Taonsa were at the heart of everything as Vasteras dominated either side of half-time, before they finally put real daylight between themselves and the visitors just before the hour mark.
Karl Gunnarsson cut in from the right before sending an aerial ball across the area for the flying Taonsa to connect with and score his sixth goal in six games, all of which came in three braces.
OIS narrowly missed the target with a couple of decent late chances, but the evening belonged to Vasteras, who are now just a point off the European places, albeit having played a game more than their nearest challengers. Orgryte remain three points from absolute safety, with those above them looking to pull clear later in this round.