Maungakaramea coach Kirsten Forrester said "Girls' High certainly stepped up and they didn't allow us to play our game."
At times Maungakaramea struggled to keep possession when exiting their defence and that allowed Girls' High to keep the pressure on. They eventually converted a penalty stroke late in the game to level the scores and force golden goal extra time.
Dropping two players and playing nine-a-side for seven minutes, Maungakaramea adapted to the new structure better and had a couple of near misses.
It was in the second period of extra time and down to seven players each that Maungakaramea were awarded a penalty stroke which Ella Gunson stepped up to convert.
The win means Maungakaramea will face Springfield in next week's semifinal after Springfield put on a dominant performance to beat Hikurangi 8-1 in their playoff.
Girls' High go through as the highest ranked losers and will face top seeds Old Girls who eased into the semifinals with a 10-0 win over Mangapai.
In the premier men's grade, Whangarei Boys' High School beat Bream Bay in their qualifier on Friday night to take the fourth semifinal spot alongside Maungakaramea, Springfield and Mangapai.