Harbour attacked from all parts of the paddock in the last 20 minutes and almost caught Dunedin, who ran out victors 32-27.
But its revival came too late because Dunedin had controlled the first 60 minutes at Kettle Park and led 32-3 when it subbed its best players.
Harbour scored four tries in its period of dominance and second five-eighth Hadley May scored three of them.
The former flanker was the best player and was backed by halfback Johnny Legg, flanker Angus Duckett and lock Nick Harwood.
Harbour had been aggressive and controlled the ball and had the edge over Dunedin in the first 20 minutes but the backline was dysfunctional.
The turning point in the game came after 28 minutes when dynamic Dunedin flanker Hugh Blake sprinted 40 minutes to score the only first-half try.
The halftime advantage was stretched to 20-3 in the first minute of the second spell, when halfback Brad Weber ran 50m to score an intercept try.
Two more Dunedin tries followed quickly and Dunedin had complete control before Harbour had its purple patch.
Dunedin 32 (Jesse Toto, Brad Weber, Hugh Blake, Tom Verdonk, Fraser Lau tries; Toto con, pen, Steph Masoe con), Harbour 27 (Hadley May 3, Ola Va'a tries; Soren Moller con, pen, Johnny Legg con). Halftime: 13-3.
