Northern was under strength, but stand in keeper Jonty Ashworth had a top game, and on the left wing, Tadhg Kelly showed the family's eye for goal when he shocked Green Island with a brilliant individual shot that beat Josh Dijkstra in the 12th minute.
A slick passing Green Island consistently carved through Northern's ranks, but earned ball possession only at the expense of penetration, and the home defence stood firm.
In counterattack, Northern was directness personified, as long passes sought target man Angus Milne, and the elusive Dave Henderson. Craig Wilkinson led the midfield battle and won healthy second phase possession.
The Island attack should have done better _ coach Malcolm Fleming lamented ''too many ineffectual square passes'' - and despite space on the wings and some searing runs by Connor Neil and Ben Kiore, the score stayed at 1-0 into the second half.
The quick footwork of David Mwangi scored the equaliser with 15 minutes to go, capping an industrious shift that included hard tackling and the ability to get past defenders.
In the final stages, Wilkinson missed an open goal, Kiore twice hit shots that trimmed woodwork and both keepers showed top skills. But as the clock ticked, substitute Jack Bowland struck the 2 1 winner past a dejected Ashworth, to the delight and relief of Island supporters dancing jigs on the touchline.
Northern coach Murray Devereux said it was typical of so many matches this season, and praised Henderson, Chris Bell and Emmet McLauren for their spirited play.
Fleming shrugged his thanks for the late result.
''It's a 90 minute game. We just needed to be better, earlier, and there would have been less drama,'' Fleming said.
More drama was enacted at Memorial Park, where 10 man Roslyn Wakari beat Mosgiel 4-2 in what coach Colin Thom described as Roslyn's best performance of the season.
Man of the match was clearly young Ben O'Farrell with two goals, two assists and a typical fetch and carry, error free midfield role that took him close to national selection this season.
O'Farrell and Isaac Nicholson gave Roslyn a two goal lead, Mosgiel climbed back in to earn a 2-2 scoreline by halftime, and it looked like the Plainsmen would take control when Nicholson was sent off.
But Rupert Mark re established Roslyn's lead and a well taken final fling by O'Farrell clinched the 4-2 scoreline.
Mosgiel's Regan Coldicott and Morgan Day reached 150 appearances at premier level, and at Tahuna Park, Tim McLennan reached centurion status with 100 appearances and Dunedin Technical player coach Aaron Burgess celebrated his 200th premier league match.
Typically, Burgess was on the scorecard as Dunedin Technical beat University 2-0, and striker Taylor McCormack also scored.
