"Under pressure we coughed up the ball a couple of times and they scored off them, and that was the difference.
"The blokes are improving, and that's the main thing, but we'd just like them to be there a bit quicker."
Border coach Ross Williams was pleased second-five Andy Hamilton and halfback Lindsay Horrocks worked out that Kaierau coming up quick and their fullback Ace Malo was lurking in the backline switching accordingly to kick-and-chase tactics.
"That actually stole my halftime speech. The space was behind, that was them analysing the space," Williams said.
"If you can get them thinking, in this heat, at the start of the season, it's exciting."
Williams said the pack had stepped up after the loss to Pirates the week before, with No8 Kieran Hussey and flanker Sikeli (Bobo) Ulukuta being the best on show.
Despite dominating territory in the final quarter, Border had issues with their lineouts and scrappy ball which prevented them scoring more.
Nonetheless, Williams said, "we floated our way through, but that's where good teams want to be".
In the heat, some hard tackles by both teams had tempers fraying at times.
After Malo landed a 45m penalty just over the bar to open the scoring, Border replied when Hamilton's grubber kick found no-one at home Haerewa able to wait for the kind bounce before diving over.
Malo added a second penalty in front, then Kaierau winger Taylor Kirkwood swooped on a loose Border pass and outsprinted his pursuers to the other end.
Another Malo penalty extended Kaierau's advantage to 16-7 before Border again went to the chip and grubber kicks the first leading to a Kaierau infringement for a Ulukuta penalty, then Haerewa grabbed his second try after winger Ben Aiken kept it on the toe.
Horrocks then finished off winger Sailosi Naqiso's dash as Kaierau had again coughed up the ball out wide, right on halftime.
The home team regained the lead straight after the break as reserve back Petia Vui was able to run glide through a gap in the Border forwards, with Malo nailing his fifth straight kick from the sideline.
However, lost ball in the backline cost Kaierau dearly as Border were able to scramble and recover.
Hamilton combined with first-five Terau Mana Wirihana to put Haerewa over for his hat-trick, then Kaierau reserve forward Rob Lavin's promising break came unstuck with Naqiso running the ball all the way back before hooker Cole Baldwin crossed for the match-winner.