Underdogs Otangarei Knights triumphed 28-22 over minor premiers Takahiwai to progress to next week's grand final against defending champions Hikurangi.
It wasn't perhaps a classic game of rugby league but the number of twists and turns involved turned it into a real thriller that held the crowd on the edge of its seat at Toll Stadium.
The lead changed four times in the match, which ended with Takahiwai hot on attack as they tried to find a converted try to send the game into extra time.
Knights' captain and playmaker Herewini Edmonds said he was proud of how the team came together on Saturday but admitted they needed a bit of luck to get past the form team of the competition.
"I'm a firm believer in luck. We've played Takahiwai twice this year and lost both times, so this time it was third time lucky for us today," he said.
"It was really tough when Taka really brought it to us, especially when we were down to 11 players, but everyone in the team believed in each other and we came through," Edmonds said.
Both sides felt the pressure early in Rugby League Northland's Multikai Cooker premiership semifinal and unforced errors dominated the first spell.
Bryce Rauahi shocked Takahiwai fans by grabbing an Edmonds' chip kick out of the air to score early on, but the try sparked Takahiwai into action and outstanding centre Ross McFarlane scored to give his side a two-point lead after Joel Freeman's conversion.
Takahiwai enjoyed their best period of play after that with the forwards gaining good metres combining with the backs to heap pressure on the Knights.
Knights' veteran Jackson Katene was sin-binned for failing to release a tackled player close to the line and was followed shortly afterward by Joshua Murray, whose similar offence clearly frustrated referee Grant Wharehoka.
Down to 11 it seemed likely that the minor premiers would cash in, but the Knights' tenacious defence frustrated them before two fantastic examples of sidestepping gave the underdogs an unexpected 14-6 halftime lead. Firstly Edmonds stepped through some loose defence around the ruck to score under the posts, then with three minutes to go Buddy Grey shaped to kick on the fifth tackle but then ran around three defenders to score the try of the match.
Momentum swung around again after the break. When the ball flew out the back of a disrupted Knights' scrum Freeman was first to react. He toed the ball into the in-goal but was illegally prevented from winning the race to the ball and a penalty try was awarded. Takahiwai took back the lead at 16-14 when Rikki Tarau was the first to put downward pressure on a wickedly bouncing ball in the Knights' in-goal.
Otangarei surged back and Takahiwai's Nicholas Godfrey was binned for holding down in the tackle before Dane Tito finished a flowing Knights' move by scoring in the corner. Ahead 20-16 the Knights had a couple of narrow escapes. A knock-on meant Manu Tuhoro's try was disallowed then Tarau just failed to hold on to a difficult kick right on the goal line.
Luck remained on the Knights' side when centre Zion Rota pushed past some tired defence to score the game's decisive try under the posts.
Ahead 26-16 with less than 10 minutes remaining Takahiwai mounted a final comeback with Sidney Akatea dotting down under the posts to make the final three minutes of the match seem a lot longer to Knights' supporters.
The game ended with Adam Donaldson busting a tackle in the Knights' red zone, but his flick pass failed to find a Takahiwai teammate and the ball was snapped up by the Knights, leading to the hooter and long and loud celebration by the Knights' supporters.
Takahiwai coach Mark Freeman said the bounce of the ball just didn't go their way.
"We had a lot of opportunities but we didn't finish enough of them so it never really happened for us. I think they wanted it more than us and they got it done," he said.
In the early game at Toll Stadium, Hikurangi Stags beat Hokianga Pioneers 34-10 to earn the chance to win their fourth successive RLN Premiership this weekend. The Pioneers put up a good show in the first spell to trail by just a try at the break but with the wind behind them in the second spell, the Stags were too good.