The victory sealed a 3-2 aggregate win in the relegation round, ensuring AGF remain in the Danish top flight next season.
The former Central Coast Mariners star was heavily involved in the game earning Player of the Match honours.
The win caps off an impressive maiden season for AFG by Amini, who made 32 league appearances, five cup appearances and scores five goals.
His exploits earned his a Socceroos debut, with the 24-year-old featuring as a late substitute for Mile Jedinak in March's FIFA World Cup qualifier against the UAE.
The news wasn't as good for fellow Australian Awer Mabil, who was a 71st minute substitute as his side Esbjerg were relegated with a 3-2 defeat to Horsens sealing a 4-3 aggregate loss.
Mabil is on loan at Esbjerg from parent club Midtjylland.