Hamilton Gold were cruising at 97-4 before losing three quick wickets to be in trouble at 128-9.
A late rally saw the side reach 146 before wicketkeeper Trigg took a sharp catch off a ball by off-spinner Webb to end the match. Braedyn Hutchinson-Walters (3-24) and leg spinner Billy Alexander-Crawford (3-21) were Northland's top bowlers.
The match was also notable for a bizarre interruption when a sheep - escaped from a nearby abattoir - ran across the pitch, pursued by a sheep dog.
The sheep was bailed up by the dog and wrestled to the ground by a woman who owned the dog.
Northland started strongly against Bay of Plenty Coastlands on day two of the tournament, scoring 184 for 4 off 40 overs. Number three batsman Kian Bird top-scored with 76 not out, batting much of the innings with opener Sam Webb (65). Max Turner closed out the innings with 17 off 12 balls, including one of only three sixes hit during the tournament.
However, Northland's bowling and fielding effort in deteriorating wet weather was not as strong as BOP Coastlands', whose batters cruised past the Northland total with four overs to spare.
The team needed to finish the final day strongly, and did so, knocking over Bay of Plenty Lakelands for 68 runs.
Braedyn Hutchinson-Walters took 4-6 off five overs, with Nathan Parkes and Billy Alexander-Crawford each snaring two wickets. The 68 was chased down in the 18th owner, with all-rounder Max Turner promoted to opener and top-scoring with 28.
Hutchinson-Walters ended the tournament with eight wickets - nine when the two pre-tournament matches were taken into account - placing him on top of the bowling statistics for all Northern Districts primary (up to Year 8) players.
Northland had won both its pre-tournament matches, including a rout of Hamilton Black for 32. Openers Luke Trigg and Sam Webb chased down the total in the fifth over.
The quick chase proved invaluable later in the tournament, when net run rates were calculated. Nathan Parkes, in his first match after a layoff for a broken arm, took three for four.