Otago scored early in the second spell and held on to beat North Harbour 24-13 at Forsyth Barr Stadium this afternoon.
It is the home side's sixth consecutive victory and cements it at the top of the Championship standings in the NPC.
Otago has not lost to North Harbour since 2010 and its scrambling defence proved impenetrable in final 40 minutes. It was the second game in a row Otago has kept a team scoreless in the second half.
North Harbour certainly had opportunities to cross the chalk, particularly on the left flank. But someone always got in the way of the last pass.
In the opening 40, Otago got ahead with two penalties to one but got a break courtesy of the TMO, Chris Hart, in the 12th minute.
Lock Tom Franklin got his arms through a tackle but looked to have lost the ball forward while trying to offload. Prop Craig Millar scooped up the ball and ran 20m to score.
Hart ruled the ball was traveling backwards when it left the hand.
Fletcher Smith missed the conversion but added a third penalty to stretch the lead 14-3 with 20 minutes gone.
Otago had an opportunity to add more points when Paul Grant bust a tackle and offloaded to James Lentjes. The home side swept up field but the movement was killed off by a stray pass which went in behind the attackers.
Having survived the scare, North Harbour swung on to attack. Second five-eighth Michael Little scampered through a hole and found abrasive centre Matt Vaega, who went over.
Harbour cut the lead to a point when Bryn Gatland knocked over a second penalty.
The home side threatened to score right before the break thanks to another burst by Grant. Smith chipped for the corner but Lentjes was not able to control the ball.
Otago struck early in the second spell with halfback Jonathan Ruru making a determined charge at the line and dragging a few defenders with him. Hooker Sam Anderson-Heather picked up the ruck ball and burrowed over.
Smith proved his worth on defence with a couple of big plays. He made a covering tackle which snuffed out a promising attack and came up with a crucial an intercept earlier when North Harbour had an overlap on the outside.
Otago 24 (Craig Millar, Sam Anderson-Heather tries; Fletcher Smith con, 4 pen), North Harbour 13 (Matt Vaega tries; Bryn Gatland con, 2 pen). Halftime: Otago 14-13.