Despite the argy-bargy and the mud wrestling, the game stayed 15 v 15, and Border began to execute their game-plan on either side of halftime, winning a couple of tighthead scrums. Promising No 8 Semi Vodosese swept through tacklers for a great individual try and lock Jack Hodges dove across off the back of the maul from a perfectly executed lineout drive.
Flanker Angus Middleton fought with Taihape every step, while Lindsay Horrocks and Craig Clare looked to keep parity in the territory kicking duel with the Whales – Dane and Luke – who have mastery of that style on home turf.
But from 21-17, Taihape lifted another gear as they pulled the match into a close-quarters war, while Border, without an injured Hamish Mellow (calf strain) and Toby Lennox, dressed to play but being kept under wraps, did not have quite the normal depth on their bench.
The tightheads stopped, and Taihape held up multiple ball carriers to force turnovers, while in the air at the lineout they started to steal opposition throws.
Border's fast outside backs could not get their usual traction in the mud, and with six minutes remaining, they could not stop Tiari Mumby, as the small but elusive reserve winger left Vereniki Tikoisolomone grasping at air as he squirted through out wide for the match-winner.
After 15 tries in seven previous games, it was the first time Tikoisolomone had not dotted down this campaign.
"It's just good to get a win, sure, against anyone, but against the top dogs, we'll take that," said Taihape coach Tom Wells of their first victory over the South Taranaki club since 2019.
"I thought it was a great game, in the conditions. The mud's always going to help us against their outside backs, they're lightning quick.
"We'll welcome the mud and hope it keeps coming, but we got to learn to win on the dry track, like they have to do on the wet track.
"Got the shield, which is bloody good. It's not really as important to us [as the championship], but, yeah, let's hold onto the bugger."
With his team still leading the points table by a comfortable points differential, Border coach Cole Baldwin was philosophical.
"It's a good reality check for us – we're not as good as we think we are.
"Taihape played well and held onto the ball.
"Everything's fixable, I'm not stressing about it too much, it's come at a good time for us, to be fair.
"But I don't want to take anything away from Taihape, they deserved that and good on them."
Taihape 28 (C Paringatai, P Hay-Horton, D Gallien, T Mumby tries; D Whale 4 con) bt Border 17 (S Vodosese, J Hodges tries; N Harding pen, 2 con). HT: 21-10.