Kaikorai's inside backs and loose forwards were key contributors to a convincing win over Harbour at Watson Park.
Kaikorai scored three tries to one, dominated play territorially, and would have won by more had its passing been more accurate.
It led 8-7 in an intensely-contested first half and would have been ahead by more had last passes stuck, but two good tries in the second spell made the match safe.
Tomasi Palu was a mercurial runner from halfback, scored one try and several times opened up the defence while Cam Rutherford was a steadying influence at first five-eighth.
Kensak Palepoi was dynamic from No 8 and blindside flanker Jamie Williams was almost as effective, their strong running testing Kaikorai defence.
Seko Kalou and Shaun Thomas gained good line-out ball, Matt Direen was strong in midfield and fullback Danny van der Voort was especially dangerous with his elusive running from fullback.
Harbour lacked the intensity it shows at its best and it missed the leadership of hooker Peter Mirrielees, who had been called into the Highlanders.
Johnny Legge was an accomplished halfback and Siaosi Folau was a hard runner at centre but the Harbour forwards did not win enough ball to achieve much fluency or continuity.
Kaikorai 20 (Tomasi Palu, Kensak Palepoi.
Jamie Williams tries; Cam Rutherford conversion, penalty goal), Harbour 7 (Siaosi Folau try; Craig Sneddon conversion).
Halftime: Kaikorai 8-7.
Referee: Doug Rodger
