Mounting infringements by Marist allowed Kaierau skipper Ethan Robinson to take advantage as his team began to build traction entering the final quarter – landing three penalties in front over the space of eight minutes to hit the lead 21-15.
However, led by skipper Brad Graham, who squared up to virtually every Kaierau forward at some stage in the fixture, plus some fresh impetus from their bench, Marist did not just fade away as a succession of penalties saw them in position to charge at the line, putting lock Brad O'Leary across with seven minutes left and silencing the Country Club faithful.
Kui stepped up for the pressure conversion, which was in a handy position, bringing back memories of the last time Marist could have upset a top team, yet missed out by one point against Byford Readimix Taihape in 2020.
But the teenager slotted it, both touch judges taking an extra moment before raising the flags, and with seven minutes left, Marist hung tough and got another couple of penalties at the breakdown to stay clear of their danger zone for a fulltime whistle that sent them whooping.
"They're feeling really bloody good, and rightly so too, because they've worked blimming hard all year," said delighted coach Travers Hopkins, who has his first win over a top-rank opponent.
"We've seen it in patches, a good half against Border, and 20-minute patches, but today it kind of stuck in.
"I'll be honest, once they got those penalties towards the back end I thought, "aw, come on lads".
"But I think, since that Taihape game, that big thumping, we've been building."
To get four competition points before they face McCarthy's Transport Ruapehu and Settler's Honey Ngamatapouri is priceless – Marist now eyeing up their first semifinal berth since 2017.
"It's been a goal of ours from the start of the year and this makes it a little more achievable, but we're also not naive to the fact we've got some hard work ahead of us," said Hopkins.
He praised his Kui for having a Boys Own Annual kind of day.
"He's a lot more mature than his age, he had some really nice touches and bear in mind he's only played a couple of times at standoff, he's normally a winger.
"He's got work-ons, as does everyone, but he's a very bright talent and very bright future in rugby.
"Jo [Bogileka] does what Jo does, hurts bodies and stuff like that. Brad Graham again, not enough can be said about that guy – week in and week out puts his body on the line.
"For those older guys, it's been a while, the Viki [Tofa]s and the Bogilekas and the Grahams, they deserved that today."
Kaierau coach Carl Gibson had to restructure his backline three or four times during the game, starting from when Ezra Malo was helped off.
"Lose Ace as well, someone else, so you're down to [20], but those are excuses and we've got no excuses – Marist outplayed us today, they won and they won well and they deserved everything they got.
"They brought everything in that first 20, and then they hung on, hung on when they needed to.
"To be fair, there was a lot of other things we didn't do well. Didn't use the ball well enough in the first half, we just tried to go where we couldn't go.
"You just got to play what's in front of you sometimes and we probably missed that today."
Marist 22 (R Kui, R Gudsell, B O'Leary tries; Kui pen, 2 con) bt Kaierau 21 (J Rokotakala, J Edwards tries; E Robinson 3 pen, con). HT: 15-12.
