Derby matches are never a foregone conclusion, but few expected AIK, without a win in over a month, to stop Hammarby from getting back to winning ways after they were surprised by GAIS last time out.
But Gnaget not only stopped them, but took all three points for themselves after coming from behind. After a goalless first half, Hammarby went ahead three minutes after the break, as Montader Madjed's shot was blocked before Ibrahima Fofana raced onto the loose ball and struck it low into the net.
10 minutes later, it was all-square again when Kevin Filling got to the byline and pulled the ball across a crowded six yard box where Bersant Celina had an effort blocked before Johan Hove volleyed in the rebound.
A clash between Celina and home goalkeeper Warner Hahn saw temperatures threaten to boil over, but six minutes from time it was Celina who won that personal duel for good, collecting Stanley Wilson's pass and firing through Hahn at the near post to win it for AIK.
The win sees AIK climb to ninth having taken their points tally to 12. Bajen will lose second place in the table if there is a winner between Hacken and Elfsborg on Monday night.
A bad day for Hammarby was worsened by them losing further ground to Sirius, who went eight points clear at the top thanks to a fourth win in a row and putting an end to GAIS six-game unbeaten run.
As for whose positive streak would continue, the early indicators all pointed to the home side, who went ahead in the sixth minute, when Isak Bjerkebo cut in from the left wing, shrugging off GAIS challenges as he went, before poking the ball home from 18 yards out.
But the away side needed only 10 minutes to show why they were one of Allsvenskan's form sides - the Sirius defence couldn't deal with a high ball into the box, allowing Samuel Salter to square it to Rasmus Niklasson, who curled it past the rooted goalkeeper.
However, the key third goal of the game arrived just before half-time - Sirius turned the ball out to Victor Svensson on the right wing, and his cross found Victor Ekstrom, who took one touch to bring the ball under his spell, and a second to drill it across the goalkeeper and into the far corner.
10 minutes from time, Mohamed Soumah was rather unfortunate to be shown a straight red card as he clashed with GAIS players following a foul, but the 10 men were able to hold on regardless for another three points. The Mackerels remain in eighth, above AIK on goal difference.
While AIK ended their recent struggles, there was no end to Malmo's poor form, as they lost for the fourth time in a row - coincidentally since an away win at AIK nearly a month ago - going down at home to newly-promoted Vasteras.
Miguel Angel Ramirez's side looked to be turning a corner when they went ahead after a quarter of an hour, when Adrian Skogmar powered the ball into the bottom corner after Theodor Lundbergh laid it back.
But the hosts were stunned by two strikes in the final 10 minutes of the first half - Jens Magnusson's cross from the right evaded everyone in the box and bounced in off the post, before a half-cleared free-kick was met by a screamer of a volley from Herman Magnusson out wide on the left.
With 16 minutes to play, MFF thought they had spared their blushes when Daniel Tristan Gudjohnsen took down a cross and squared for Erik Botheim who bundled the ball into the top corner, only for the visitors to win it in the second minute of added time.
The Malmo defence allowed Simon Gefvert time out wide on the right to swing a cross right onto the head of Mikkel Ladefoged, who buried the chance and sent the pocket of away fans into raptures. The record champions are 12th in the table, passed by Vasteras who join AIK and GAIS on 12 points each.