The victory was just their seventh in 38 games against Auckland, and it was on the cards from the off, when Shaun Stevenson opened the scoring by finishing off a scathing 60 metre move down the right wing.
Harbour had all the early running, and their young backline were dominating their more experienced counterparts. Tevita Li was the most prominent, carving up on the left wing, beating eight defenders, gaining 126 metres and nabbing two tries in an extremely elusive display.
With Bryn Gatland providing plenty of ball for the backs as part of a 22-point outing, there was room to run at will, with Harbour breaking the line on 12 occasions as Auckland dropped off 21 tackles.
Auckland had their chances early, but Harbour's defence held strong, and then turned their territorial advantage into a dominant showing on the scoreboard.
An 18-3 halftime lead was extended through Stevenson's second try, and Li also bagged his double as Auckland were starved of possession, and floundered in defence.
As the score ballooned - Auckland conceding 50 points for the first time since 2013 - the trouncing continued, with hooker James Parsons streaking away for a 50-metre intercept try.
That moment seemed an apt nail in the coffin for Auckland, but even that wasn't enough, with two further late tries only extending a historic humiliation.