Sixteen goals had been scored in AIK's three straight wins before a goalless draw at Malmo last time out, and the home side had the chance to end that mini drought midway through the first half after Mattias Hellisdal committed a handball inside his own penalty area. Goalkeeper Elis Jager went the right way, but Johan Hove's penalty was just too good.
Any hopes the hosts had of another low-scoring encounter were ended on the hour mark, when Jens Magnusson collected a pass on the turn, cut into the box from the right and guided the ball into the bottom corner to draw Vasteras level.
Less than 10 minutes later, the visitors were in front when a swift attack looked to have gone awry when Magnusson was denied a second by a block, only for Mamadou Diagne to pick up the rebound and fire through the crowd. Vasteras then notched their third in 11 minutes when Jonathan Karlsson found Ismet Lushaku, who cut in from the left and curled the ball past Kristoffer Nordfeldt and into the far corner.
And the AIK capitulation was completed just seven minutes later when Simon Gefvert got free on the right and cut the ball back for Abdelrahman Boudah, whose first-time strike deflected off a defender and clipped the crossbar on its way in.
It's a second away win in a row for the green and whites who sit sixth, only behind AIK on goal difference, though Gnaget still have a game in hand.
Goteborg are now 10 points clear of the bottom three thanks to a narrow win at home to Halmstad, their third victory in a row as their unbeaten run stretches to four matches.
Sam Larsson put the homse side ahead with his fourth goal of the run, blasting a 20-yard free-kick into the top corner which goalkeeper Tim Ronning couldn't keep out despite his best efforts.
Blavitt were two goals to the good seven minutes into the second half, thanks to a strike from even further out from Felix Eriksson, who received Noah Tolf's square ball and unleashed a powerful effort from over 25 yards that swerved away from the helpless Ronning.
In the final 20 minutes, David Kruse was guilty of fouling Marvin Illary inside the area and Rocco Ascone sent the goalkeeper the wrong way from the penalty spot, but Goteborg held on for another three points that take them to ninth in the table, while two losses in a row keep Halmstad eight points from safety.