Southern and Dunedin had to settle for an 18-18 draw. Harbour was too good for University, winning 31-6, while Kaikorai overcome a spirited Green Island 27-17.
Zingari-Richmond climbed one place with a 31-19 win against Alhambra-Union to complete its season in pleasing fashion. Taieri had the bye.
Kaikorai: 27
Green Island: 17
This game illustrated just how much tighter the competition has been this year.
Kaikorai was already through to the semifinals while Green Island was trying to get off the bottom of the competition table.
It might have been expected the game would be a walkover for Kaikorai, but it was forced to do a lot of defending.
It scored a couple of opportunistic tries to clinch the win 27-17, and was definitely the more potent of the teams on attack. But Green Island's forward pack stuck to the task and rumbled the ball upfield in the mud at Bishopscourt.
No8 Simon Tupu had an outstanding game and put pressure on the defence when he carried. Replacement back Latu Siaki took a lot of tackling and second five-eighth Hayden McBride made several line breaks.
Kaikorai opened the scoring through hard-working centre Danny van der Voort. Fullback Matt Jones drilled the conversion and had a perfect day from the goal-kicking tee with five from five.
Halfback Devin Stapley replied, diving over from close range, and Green Island continued to have the better of the half. But Iakopo Mapu, who had a storming game, collected a fumble from Green Island and ran 55m to score and help give his side a 14-10 lead at the break.
Kaikorai loose forward Pita Sinamoni scored another fortunate try 15 minutes into the second spell. It appeared as if Blair Tweed, who must have made a thousand tackles, knocked the ball forward at the front of the lineout moments earlier.
Southern: 18
Dunedin: 18
Dunedin came out of the blocks at pace and totally dominated the first 35 minutes of this game. Its set piece was accurate, the scrum dominated and its pick and go game ate up big metres.
It transferred that domination into a 15-point lead after 35 minutes of the first spell at Bathgate Park. The first try went to flying winger Zac Harrison-Jones after a searing break by flanker Hame Toma, who then fed the winger for him to scamper away.
Harrison-Jones repaid the compliment when he fielded a kick and beat four tacklers to set a ruck deep in Southern territory. The ball went wide quickly from that ruck for Toma to go over.
At the end of the first half, Southern got its hands on the ball and after four or five dabs at the line, prop Mike Mata'afa scored.
The second half was a complete reverse of the first and was owned by Southern. It scored early in the spell when No 8 Mika Mafi crashed over after a series of pick and goes.
Dunedin extended the lead to 18-10 but Southern replied soon after with an opportunist try to winger Ben Leggett, who picked up a loose ball from a ruck and tiptoed down the sideline to score.
Dunedin's lineout then went wrong, as did its kicking game, and Southern had a lot of ball and territory. Somehow Dunedin held it out with stoic defence for long periods and all Southern had to show for its dominance was a solitary penalty to Josh Ioane to draw level with 10 minutes left. Southern was left to rue an off day with the boot.
Dunedin had a chance to win the game with a long range penalty attempt to replacement first five-eighth George Witana but it flew just under the bar.
For Dunedin, there was great service up front from Don Brighouse, massive work-rate from lock Mark Grieve Dunn and the ever menacing Toma. Leroy van Dam was a colossus in the midfield and winger Harrison-Jones proved what a danger he can be.
For Southern, hooker Cameron Keech was tireless up front and pinpoint at lineout time. Adam Knight and Mafi were the most potent ball runners. Centre Paul Tupai carried well in the midfield and Leggett and fullback Josh Buchan looked dangerous every time they touched the ball.
Harbour: 31
University: 6
The Harbour forwards were an eight-man human battering ram that smashed the students in all phases in the mud at Watson Park.
The ground was a quagmire but it did not slow the Harbour pack.
The handling of the Harbour backs and forwards was remarkable in the conditions and this put pressure on the University defence.
The powerhouse Harbour scrum kept pushing the students backwards. Key players in this phase were hooker Sekonaia Pole and locks Sione Misiloi and Chucky Koroi.
Harbour had a two to one advantage in the lineouts, where Misiloi and flanker Ben Whale were dominant. Three of Harbour's five tries came from forward drives after a lineout.
The students attempted their own forward drives but they were met by a strong defensive wall led by No 8 Charles Elton.
The conditions were difficult for backs but, led by the inside back combination of Vinnie Isherwood and Logan Allen and centre Hemaua Samasoni, the Harbour backs added pressure.
Harbour scored two tries and led 12-6 at the break. It took the students out of the game early in the second spell with a counterattack from its own half to stretch the lead to 13 points. Harbour added two late tries with forward drives from lineouts.
The best student forwards were hard-driving prop Callum Hardie, lock Josh Dickson who took six clean lineouts and flanker Sam Dickson. First five-eighth Fletcher Smith gained territory with his tactical kicking.
Zingari-Richmond: 31
Alhambra-Union: 19
Zingari-Richmond pulled off its fifth win this season and climbed one place on the competition table following its 31-19 win against Alhambra-Union.
The Colours finished ahead of Green Island and Taieri and have the same number of wins as traditional powerhouse University, which it might might be remembered, beat Zingari 137-0 just last season.
No-one in the club will need any reminding about that terrible day, so it can be well pleased with the progress made this winter.
It laid the platform for its win with a solid effort up front. The pack carried the ball into contact strongly, it scavenged for possession well and forced Alhambra-Union into mistakes through defensive pressure.
Alhambra helped engineer its own demise. It had an opportunity to open the scoring in the second half but lost the ball over the line.
Its lineout did not function well and it found itself playing without the ball for long periods, particularly in the first half.
Highlander Joe Wheeler was sin-binned with nine minutes left in the first half for a dangerous tackle, while Zingari's Eli Tonga got put in the bin with about 10 minutes remaining in the match.
Zingari loosie Lafaele Faamoe scored two tries and was the pick of the forwards. First five-eighth Thomas Johnson was sharp at pivot, while Ciaran Gaffney was threatening when he was in space and had a good match.
For Alhambra, hooker Alex Frood was solid and kicked two conversions. Lock Hayden Fleury was busy and halfback Caleb Gray provided some good service.