Hacken had the chance to reclaim second place and close the gap at the top to Sirius to six points, but their plan A went out of the window four minutes in when they failed to clear a ball into the box which dropped to Oskar Fallenius, who fired home.
The hosts got themselves level when a neat move was finished off by Julius Lindberg tapping in Adrian Svanback's ball across, but Djurgarden were back in front again before the break, when Kristian Lien nodded in a Max Larsson corner.
Lien put real daylight between the sides 17 minutes from time when he was quickest to react to a rebound and completed his brace, but it was game on again 10 minutes later when Bamir Sadiku bundled the ball in from close range.
However, the points were sealed by the visitors in the 86th minute when Hacken were undone by another simple corner routine - this time it was Bo Hegland delivering and Nino Zugelj heading in unchallenged.
There was still time for Mikael Marques to be sent off in added time for a poor challenge just five minutes after coming on, but Djurgarden comfortably held on to end their two-game losing run. They climb to fifth, two places and four points behind Hacken.
Djurgarden overtook six teams in the table with that one win, and two of them were Brommapojkarna and GAIS, who missed the chance to really close in on the European places with a draw in the suburbs of Stockholm.
The home side took the lead after 20 minutes, when Oliver Berg met Mads Hansen's cross with a looping header, but the lead lasted just over a quarter of an hour, when Robert Thorkelsson's shot from a tight angle was parried, but only to Henry Sletsjoe, who made no mistake on the rebound.
GAIS struck the woodwork twice in a second half they dominated, only for Lukas Bjorklund to waste a golden chance to win it for BP in added time. GAIS sit sixth and unbeaten in two, while it's four unbeaten for BP, though they find themselves back in ninth, albeit only with goal difference separating the teams.