A five-try bag to Harbour's George Folau put the dampers on his opposite's 50th premier division one game for Green Island.
Any celebration for second five-eighth Sam Eriepa reaching his half-century in style were quickly shouted down as Folau helped expose weaknesses in the Green Island backline with his support play and strength in the tackle.
Green Island were well-served in the forwards, but all too often were exposed in the backs through poor option taking, from which Harbour prospered.
Harbour No. 8 Dalton Ellis, lock Sam Ready and prop Greg Restieaux were the pick of a well-tested forward pack and Lex Kaleca provided solid defence in midfield. Fullback Ollie Cuthill and wings Afi Tusa and Damien Keen provided good service out side.
Keen providing the platform for Folau's first try when he was left to run 70m up field for Folau to take the off-load and run in the five-pointer.
Cuthill began the match with 93 points for the season and easily surpassed the three-figure mark with a match haul of 22 points, his tally surpassed only by Folau's five-try blitz in the first 50min.
Green Island toiled away in the forwards and at times appeared to have the edge. Mika Mafi, Andre Clarke and Jackson Hemopo put in a tireless work-rate that all too often was undone when the ball went wide.
Harbour 52 (George Folau 5, Afi Tusa, Ollie Cuthill tries; Cuthill 4 con, 3 pen), Green Island 39 (Roma Saulieoge, Tala Moli, Joe Bartlett, James Spooner, Kail Spooner; Bartlett 4 con, 2 pen). Halftime 23-20.
