The 29-year-old Dane left Modo after the relegation and moved north.
In his first northern derby, he became a big match hero and the supporters sang his name afterwards.
Really fun that the fans get carried away, the extra support gave us three points tonight, says Aagaard to TV4 Play.
When Mikkel Aagaard completed his hat-trick in a numerical advantage with just over nine minutes left, it meant Skellefteå's winning goal at the same time.
Then Skellefteå had lost both 2–0 and 3–1 in the prestige match between the two winners of the last two years' Swedish Championships.
There is a belief that regardless of how it goes, one looks ahead. Fantastic fun that we don't give up, he says.
Skellefteå climbed past Luleå and up to sixth place. The reigning championship team from Norrbotten is in tenth place.
Frölunda tops the table on 18 points and 3–1 at home against Brynäs was the sixth win in seven matches. Max Lindholm scored two goals.
Brynäs, Swedish Championship finalist in the spring, has lost five of its seven first matches and is twelfth.