Auckland started the final stronger in search of their first national title since 2009 with talismanic striker Tegg hitting the frame of the goal in the first half, and headed a late chance straight at goalkeeper Pam Yates.
A couple of half chances to Tegg and Hannah Kraakman were the closest Auckland came to breaking Northern's resolve. The defending champions too could only muster a handful of openings in the first half, as the cross town rivals headed into half time locked at nil-all.
"The first 45 minutes was intense and there was a lot of nervous energy but the second half was excellent and the team showed that they are a great, great team," said Donoso.
Shortly after the restart a teasing cross from Harrison from the left bounced invitingly in the area for O'Brien to head unopposed past Erin Nayler. O'Brien had come close to opening the scoring moments earlier with a curling effort which went wide of the Auckland goal.
The lead was extended on the hour when a long range Harrison free kick was palmed onto the cross bar by Nayler, unfortunately for the Junior Football Ferns custodian the rebound fell at the feet of Brown to bundle home.
Donoso said the win was testament to the depth of talent within Northern Football, with only six girls remaining from last season's title winning side.