North Harbour should of made more of the gale force gusts of wind they enjoyed at their backs during the opening stanza but their kicking in general play wasn't accurate enough.
Manawatu didn't make the same mistake though. They took full advantage of the Palmerston North wind in the second spell as Nehe Milner-Skudder scored in the corner in the 41st minute.
Harbour struggled to muster any continuity on attack as the wind got even stronger as the game wore on and the brave few who sat in the terraces were rewarded when hooker Rob Foreman crossed for Manawatu's third from a botched lineout.
Turbos pivot Jade Te Rure found it tough off the kicking tee as he missed his three conversion attempts but as their score moved up by fives they had no cause for concern.
As the clock ticked past 68 minutes, Manawatu had a penalty in handy position to the posts but they went for the lineout as they searched for their fourth try in a bid to lock up a vital bonus point.
But they spurned the set piece and shortly after North Harbour fought back in to the game as debutant Michael Little, son of former All Black Walter Little, scored his first ITM Cup try.
North Harbour could have taken a shot at goal to draw the game in the 79th minute but they didn't want a bar of that and tried to run the ball for the win but Manawatu produced some spirited defence in the final stages to hold on as they earned a late penalty.
Harbour then stole the Manawatu lineout to have another chance at victory but couldn't find a way through as Manawatu celebrated.
Key decision: Manawatu coach Jason O'Halloran took the chance to play in to the wind in the first spell and it proved a masterstroke. Manawatu slogged through the first 40 to only trail by a couple of points at the split and finished the stronger of the two sides with a stiff breeze at their backs in the second half.
Watching on: Hurricanes coach Mark Hammett was spotted in the stands watching this one. Hammett has barely picked a player out of Manawatu during his three years in charge at the Hurricanes but maybe someone in green and white impressed him today?
Manawatu 15 (James Oliver, Nehe Milner-Skudder, Rob Foreman tries) North Harbour 12 (Nafi Tuitavake, Michael Little tries; Jon Elrick con) HT: 5-7