Dunedin recovered from a slow start to score five tries in the second spell to beat Harbour at Watson Park.
Dunedin held a slender 10-7 lead at the break but put its game together in the second spell with backs and forwards making ground and applying pressure on the Harbour defence, which wilted from the constant attack.
Prop Will Henry played a key role with his driving play and his skill with the pick and go.
Loose forwards Joe Dobson and Tim Fraser were quick to the breakdown.
Halfback Robbie Smith always looked dangerous with his sniping runs, and he converted all six tries.
Fullback Sam Lawson was dangerous on the counter-attack.
Powerful centre Wayne Gibson was the best of the Harbour players, while prop Ryan Olsen had a strong game in the tight.
Dunedin 45 (Sam Lawson, Simon Davey, Joe Bradley, Simon Luke, Tom Verdonk, Josh Hamilton tries; Robbie Smith pen, 6 con), Harbour 14 (Wayne Gibson, Brad Griffiths tries; Craig Sneddon 2 con).
Halftime: Dunedin 10-7.
Referee: Adam Morrison.
