Rangiuru, who hadn't lost since they met Paroa back in round one, did more to lose the match than they did to win it.
Although Rangiuru were able to put points on the board within two minutes of the kickoff, when left winger Ra Faulkner was given some space out wide and managed to push off two would-be tacklers, both sides were guilty of being sloppy with possession and general ball play.
Paroa put points on the board through an Ariki Henry penalty five minutes later but it took another 15 minutes of dropped ball and poor option-taking by both sides before Rangiuru found any real rhythm and Matt Eru crashed over the line from a ruck to move Rangiuru into a 10-3 lead. Fullback Ngatai Kingi kicked a 35m penalty to take the lead to 13-3.
But Paroa were soon countering with their first try of the match, when Maru Henry ran through a small gap and scored under the post for an easy conversion for Henry.
Henry had an opportunity to level the score just before the break after Rangiuru were penalised at the breakdown, but his kick went astray and the score remained 13-10.
The score would stay that way for the next 40 minutes with neither side really looking likely of scoring in the abysmal conditions.
But with time up on the clock Rangiuru's discipline let them down and Paroa were given a penalty 40m out, which Henry nailed to send the Paroa crowd into raptures and his team into extra time.
The defining moment came in the fifth minute of extra time when former Steamers prop James McGougan picked up the ball 8m out from Rangiuru's line, wrong-footed his opponent and crashed over for Paroa.
McGougan pulled his calf muscle in the process but said it was more than worth it.
"Yeah, it hurts, but mate, I'm happy to live with that for us to take the win."
Although Rangiuru were able to level the score with a try to Wi Kendall in the dying minutes, Kingi couldn't convert and with Paroa scoring first in extra time the Eastern Bay side were awarded the win.
Rangiuru coach Peter Wood said it was hard to lose the match in the manner they did.
"That's finals football. To lose on a technicality like that, it's a tough one to take."
It was a battle of wet weather attrition in the division two final, where Katikati held Arataki scoreless to take out a 13-0 win.
The Bay of Plenty team had a 3-0 lead at the break before running in the game's only try to take the Baywide silverware and book a division one berth next season.
It was one-way traffic in the senior reserve title decider. Tauranga Sports led Whakarewarewa 29-0 at halftime before going on to clinch the title with a 56-0 victory.
Like the division one final, the colts championship was decided in extra time between Te Puna and Tauranga Sports. Tauranga made the early running and led 10-0 at the break courtesy of a try to John Bosco Tagaloa and a conversion and penalty goal from Geoff Berry.
Te Ohia Tuhakaraina scored a try for Te Puna in the second spell before the Tauranga side replied when Jay Michalik crossed.
With a minute of regular time remaining, Te Puna prop Tamiti Jory crashed over for a try. Shaun Borrell calmly slotted the conversion to square the game up at 15-15 and take the encounter into extra time.
Iria Peita nailed it for Te Puna when he crossed for his side's third try, with the Te Puna unit holding out to take home the McIntosh Shield for the first time in more than a decade.
