While Gisborne were reduced to 14 players after a late tackle Tauranga Boys' scored through hooker Mafi Fifita after multiple phases at the line. Cole Forbes put his team 7-5 ahead.
Gisborne then scored two tries to take a 17-7 lead into halftime that essentially won the match.
The first was a classic play out of the Beauden Barrett playbook with a cross kick from the first-five taken by the winger who set up a try in the corner. While that was all down to Gisborne's skill the second came from yet another unforced error by Tauranga that led to another long-range runaway try.
Tauranga looked more urgent in the second spell but their inability to put multiple phases together played right into the hands of the hungry Gisborne defence.
With time running out, replacement winger Connor McLeod finished well in the same corner Gisborne enjoyed in the first half to put Tauranga within five points.
Flanker Dylan Williams crashed over under the bar but was ruled to be held up by international referee Nick Briant in a game-changing moment.
Gisborne celebrated by scoring again to open the gap out to 24-12 and although Williams crossed for a try with two minutes to play it was too little, too late.
Tauranga Boys' coach Dan Goodwin was disappointed how their final home game of the season ended.
"There were a lot of errors today that let us down and brought them back into the game. We never underestimate Gisborne or any team in this competition. They are a good side and they had no pressure on them so they were always going to come out and have a crack at it," he said.
"It is just disappointing for the boys as this was their last home game. We were missing a few players which doesn't help but that is not an excuse. It is an opportunity for someone else."
Tauranga Boys' face Rotorua Boys' next Saturday in Rotorua in round one of a Chiefs knock-out competition.
"We will get four players back for that game which will make a big difference, including some of the leaders we lacked out there against Gisborne," Goodwin added.