The Invercargill player went into the last two holes 2-down in yesterday's final.
But he pulled off a remarkable comeback to deny Otago's Callum Judkins at the Otago Golf Club.
Tautiri birdied the 17th and 18th to force a 19th hole.
He completed his late surge with a third consecutive birdie to claim the title 1-up.
It had been even most of the way before that.
After being tied at the 12th hole, Judkins went 2-up, forcing Tautiri to dig deep for the win.
That good form had been on show earlier in the day as well.
After rain caused a lengthy delay to the morning's semifinals, Tautiri put on a classy display.
He beat Ryan Bellamy 5 and 4 in a dominant performance.
Three birdies in the first four holes put Tautiri 3-up early.
He held that lead through to the 12th, when a hole in one on the par-three extended that lead to 4-up.
A par followed on the 13th, before another birdie on the 14th ended the match.
In the other semifinal, Judkins won a closer match, beating Leith Campion 2 and 1.
In the division two final, Duncan Croudis won a thriller against Ben Patston, 1-up on the 20th.
In division three Joseph Hancock beat Joshua Booth 2 and 1.
In the senior women's final, Kathryn Baker beat Tracey Storer 3 and 2.
Otago Golf Club director of golf Shelley Duncan said it had been a good weekend of quality golf.
She added yesterday's rain delay meant it might have been the latest the tournament had finished, the players not completing their finals until after 7pm last night.
