HK held an advantage for most of the match against Mid Canterbury, played in brilliantly fine conditions, and led 17-5 at half-time after conceding an early try to Mid Canterbury's Seta Koroitamana.
Mid Canterbury got beaten in the forwards in the first half, failing to match the visiting forwards, and were found wanting in defence.
HK number eight forward Nardus Erasmus had a good debut marked with a try, while prop Scott Cameron also scored a try.
Fullback Himiona Henare converted both tries and added a penalty, all crucial kicks to give his side the psychological seven-point buffer.
Erasmus could be pleased with his effort and went into lock in the second half as Horowhenua-Kapiti coach Chris Wilton bought about the changes.
Wilton said he was encouraged by the courage his side showed on defence in what was a physical match.
"We took the game to them physically in the first half and then I thought we showed a lot of character and courage with our defence in the second half and the work we'd done around our defence showed," he said.
HK was unlucky not to have more points after putting the home side under immense pressure early, but spent much of the second half on defence, and it required a big effort on defence to not leak a try.
Mid Canterbury added to their tally with a try wide out to Josh McAtamney to make it 17-10, and that's where the scoreline stayed.
After pouring on the pressure in the last 10 minutes, a late Mid-Canterbury charge of at least 10 phases against the run of play nearly spoiled the party, only for the home side to come up with a late knock-on saw that saw HK hold on.
Meanwhile, HK will be without four key players this weekend in their match against West Coast at Levin Domain.
Scott Cameron, Aaron Lahmert, Willie Paia'aua and Timoci Seruwalu have all been picked for the NZ Heartland XV for a match at Eden Park.
SCOREBOARD: Horowhenua Kapiti 17 (Scott Cameron, Nardus Eramus tries; Himiona Henare pen, 2 con) bt Mid Canterbury 10 (Seta Koroitamana, Josh McAtamney tries). HT: 17-5
Photos by Heather Mackenzie