For the Tigers, ex-North Queensland Cowboys halfback Hayden Karena masterfully directed the traffic around him and set up most of their attacks around the ruck.
In the other semifinal, on field three at Resthills, Ngaruawahia and Hukanui also played out a gruelling encounter, with Ngaruawahia scoring a golden points penalty in extra time to win their match 12-10 and end Hukanui's season.
This weekend sees top qualifier Taniwharau hosting Tigers for the right to progress to the grand final on August 10 and Otumoetai host Ngaruawahia in their sudden-death playoff match at Mitchell Park at 2.30pm.
In the BOP premiers, Rotorua's Pikiao Warriors defeated Forestland Falcons from Tokoroa 36-12 and Taupo Phoenix beat Ngongotaha Chiefs 38-14. Both winners are now assured of playoffs status.