Whakarewarewa are through to the Baywide premier final after defeating Tauranga Sports 18-17 in a thriller.
Whaka had to come from behind during the match in Tauranga to claim the victory and progress to the final.
Mount Maunganui also recorded a shock win in the other semifinal, defeating favourites Te Puke 35-20.
That means Mount and Whaka will meet in the grand final next weekend.
It is unclear who will host the grand final next weekend.