When Harlem Simiona was brought down in the Otumoetai penalty area, Mitch Miller had two bites at the cherry. His first spot kick was saved by 'keeper Graeme Blissett, only for the referee to rule that Otumoetai players had encroached into the box. Miller made no mistake with the retake.
Both sides had efforts cleared off the line in the second half, but it was Ngongotaha who stretched the Otumoetai defence to breaking point with a run on the left and Josh O'Sullivan provided a cross that evaded Blissett and fell to Mitch Miller to score his second to make it 3-2 to Ngongotaha.
Ngongotaha coach Shane Davis said it was clear his side had had a weekend with no game.
''I'm proud of how they played. Having that week off showed a little bit, but they still played football, they kept it on the deck and moved it around."
The premiership winners have one more game to play, against Matamata Swifts, before heading into a home and away play off with an as yet unknown Auckland side for a place in the Northern League second division.
''They are a very good side and they've remained unbeaten," said Otumoetai coach Richard O'Regan.
''We believed we could compete with them, but we haven't had the rub of the green and conceded some silly goals."