But a midfield spill let Ratana hack the ball into Hunterville's dangerzone, where they struggled to clear as Ratana winger Alan Penetito made a couple of nice sideline catches to keep his team on attack, then halfback Rehimana Meihana slotted an excellent penalty from near the chalk to rouse the Pa supporters.
Six minutes later, veteran lock Isaac Fonotoe, who rattled Hunterville with some full-on body tackling, set his side away with a blindside dash and offload, leading to another penalty, this time in front for Meihana to give Ratana the lead at halftime.
Hunterville came out roaring in the second stanza, with prop Jamie Brett, second-five Blair Osborne, and lock Brett Illston all driving close to the tryline, as they picked up a succession of offside penalties and opted for attacking scrums.
Fonotoe, and reserve forward Scott Komene produced some awesome defence, but the weight of possession told and finally Brett drove low with support to score under the bodies in the 56th minute.
Hunterville wasted no time in bringing on veteran Scott Parkes, who immediately looked to kick into Ratana's corners, but a succession of penalties had the defending champions back on attack – No8 Marius Joseph surging at the defensive line.
However, Ratana kept their numbers light at the breakdowns, looking to set up the next carries, while Hunterville looked to make the ruck a contest and showed stonewall defence – pushing the ball runners back across the 22m.
Finally, Ratana looked to the penalty kick option, with 2020 grand final hero Brooklyn Herewini coming off the bench and taking over from Meihana, but into the breeze his attempt fell short into Parkes' waiting arms.
Hunterville then played composed rugby for the last eight minutes, grubber kicking and chipping into the corners, and Ratana could not get back out to steal the game.
It was a great way for Paul Richardson, Scott Illston and Bradley Richmond to celebrate their 50th games for their club.
"We just wanted to play in their half. I thought we did that in the first half pretty well, for the first 20, then in the second half we executed for about 35 minutes there," said delighted coach Greg Parkes.
"So pleasing, real happy that we could bring on some experienced players that could put us into those corners and keep the pressure on.
"Our forward pack has come a long way from where we have been - they compete with any side now.
"It will be a huge [party], massive, it's already started."
Ratana performed a stirring haka for their supporters after the medals presentation, and coach Leon Mason, who would have played if not for bicep surgery, took the defeat on the chin.
"All credit to Hunterville for taking away with the win today, we knew we were coming into a wet ground, our set up and everything that we had was awesome.
"But I think a couple of things that we may have missed in the first half that we should have done earlier on in the game, but, hey, can't win them all.
"Big ups to our guys for staying true, believing in themselves. We knew it was going to be a hard slog against Hunterville, a very experienced team, but proud of the boys for putting their hand up, and it showed.
"We've got a bigger vision than upon what's happening in the last two years, we're just slowing building to it – it's how we learn from it and take away from today, our future for 2024."
Hunterville 8 (J Brett try; J Williamson pen) bt Ratana 6 (R Meihana 2 pen). HT: 6-3 Ratana.
