They were dominant at the Country Club until last Saturday against Ratana when a strong second stanza could not prevent a 24-7 loss, which initially meant a return semifinal in the Pa, until Celtic upended Hunterville at Spriggens to change the itineraries.
"We just didn't execute really. Dropped ball, loose carries," said coach Brendon Lawrence.
"I would have liked to go back to Ratana, I thought we gave them a good crack that second half, but it's Hunterville, so over to Hunterville we go.
"Both would be tough games, but to win [the title], you've got to beat anyone.
"What we learned last time – we're more than capable to catch them."
In mid-May, Kaierau had been in the game until the last 20 minutes when Hunterville stepped up a gear.
"Normally, we're finishing strong, so that's the lesson for us," said Lawrence.
What did not aid their cause was that the Senior squad provided multiple players to their injury-racked Premier side.
"The Prems are our ultimate team, so our goal is to feed guys into that team.
"Anyone who steps up and comes in is more than capable."
Outside backs Matt Murphy and Justin Baty have had their baptism at the top level, while standout lock-loose forward Mason Johnson moved up and has stayed there.
Lawrence has full praise for flanker Reuben Kellow, a Senior standout who has given reliable service to the Premiers.
The injury curse has not been restricted to the top side as Johnson's former Metro teammate Coultin Wilson got hurt against Ratana, and captain Joel Martin is doubtful.
The battle-tested veterans in prop Jarrod Hook, Johnny Prince and experienced fullback Carlwyne Riddles will have to lift their team-mates against a Hunterville club that has won nine championships in 12 years