Taieri's slide down the leaderboard continued when the Eels lost 28-3 to University.
It has slipped to seventh place in the standings. However, Taieri did deny the competition frontrunner a bonus point.
Harbour smashed Pirates 52-10 with Aleki Morris plundering three tries.
Green Island scored in the dying moments to beat Alhambra-Union 31-24 after trailing by 11 points at halftime, while Southern dealt to Zingari-Richmond 38-5 and moves back into the top four.
Kaikorai upset Dunedin 23-15 through some marvellous defence.
Green Island 31
Alhambra-Union 24
Green Island prop Ross Geldenhuys barged over for three tries but it was first five-eighth Sunia Makasini who sealed a dramatic win against Alhambra-Union at the North Ground.
The scores were locked at 24-24 after Green Island had trailed 21-10 at the break but it got itself back into the game through its forwards.
Time was quickly disappearing when Green Island rumbled its way up the field.
It camped on the Alhambra-Union line for the best part of five minutes before Makasini slipped through a gap with time up.
Alhambra-Union started strongly and had the better of Green Island for the opening 20 minutes.
The home side went out to an 8-0 lead.
Green Island responded with two tries in a brief good patch but Alhambra plugged away and kept accumulating points.
First five-eighth Rhys Morgan knocked over three first-half penalties and tries to Cama Poasa and Highlander Jason Emery enabled Alhambra-Union to make big strides towards victory.
Poasa beat about three defenders on his way to the line in a cracking try, while Geldenhuys used his chunky frame and good body position to flop over for his three tries.
Loose forwards Jackson Hemopo and Makato Tosa and hooker Ricky Hollamby were also instrumental in Green Island's dominance up front.
Kaikorai 23
Dunedin 15
Perhaps it is all that sand on the surface at Kettle Park which encouraged Dunedin to play beach rugby.
The Sharks must have thought the sun was out as well as they went wide and tried to run the ball out from near their own goal line.
The ball was spilt and, shortly after, Logan Moore barged his way over.
The second five-eighth can play more like an extra forward at times and his first-half try helped set up the victory.
Kaikorai winger Matt Jones kicked superbly in the conditions, landing three penalties and a conversion to help his side build a decent 16-5 lead at the break.
The home side spent most of the first spell defending but did score first thanks to Kaikorai No8 Nathan Hull, who dropped the ball cold from the kick off.
Powerful loose forward Hame Toma took advantage and burst through a tackle to score five minutes later.
Dunedin rallied in the second half and battered away at the Kaikorai line, whose defence, to a man, was quite outstanding.
Dunedin did not adjust to the conditions as well as Kaikorai and its handling errors proved costly.
But it was still in the game until Paul Grant's piece of brilliance.
Kaikorai's scrum found several reverse gears but, while backpedalling furiously, Grant picked the ball up and charged over from 10m out to give his side an unassailable 23-10 lead.
Sam Anderson-Heather scored a consolation try in the final moments, but Dunedin was denied a bonus point when Josh Simpkins' conversion attempt struck the crossbar.
University A 28
Taieri 3
A clinical display from University A enabled it to successfully retain the Paul Sapsford Memorial Trophy at Peter Johnstone Park.
Taieri dominated territory for the greater part of the first half, particularly for the first 10 minutes when it pounded away at the University A line, but could not buy a point, given a committed University A defence.
It was University A which opened the scoring with a well-worked try to centre Shae Tucker midway through the half.
Lock Matt Davidson and flanker James Lentjes stood out in the Taieri forward pack, as did Aki Seiuli when he came off the bench in the second half.
And while Taieri's scrum held its own against a battle-hardened University pack, it was University A lock Josh Dickson who dominated at the lineout.
Dickson was full of work around the field, with the loose forward trio of Sione Teu, Dillon Hunt and Damien Scott proving a handful for the Taieri defensive screen.
Hooker and captain Sam Sturgess once again led the pack by example with props Angus Williams and Callum Hardie gaining valuable ground with the pick and go.
On a day fit only for ducks, and with the University A pack dominating broken play, the backs were not afraid to chance their arm.
Only commitment from the Taieri outside backs kept the student side at bay and denied it a bonus-point fourth try.
Southern 38
Zingari-Richmond 5
Rugged hooker Hame Faiva played a barnstorming game to help Southern beat Zingari-Richmond 38-5 in wet and cold conditions at Bathgate Park.
He was a ferocious tackler, dynamic with ball in hand, and scored the first try.
Prop Junior Sala led the way as the Southern forwards made ground with the pick and go.
They also dominated the lineout and took six takes off Zingari throws.
The other standout forward was flanker Andrew Sanders, who won his share of lineout ball, was strong on the burst and safe on defence.
The Southern backs played sparkling rugby and the ball handling in the wet conditions was outstanding.
This was helped by the accurate long passing of halfback Josh Walden, the counterattacking skills of fullback Bryce Hosie and the speed of wing Josh Gordon, who outflanked the defence with an 80m try in the second spell.
Southern scored four converted tries to lead 28-0 at the break.
Zingari lifted its game and had a more disciplined defence in the second spell.
Tighthead prop Chris Preddy anchored the scrum to give Zingari parity with Southern in this phase.
No8 Lafaele Faamoe made strong bursts with the ball in hand and flanker Chris Bell had his normal solid game.
Harbour 52
Pirates 10
Aleki Morris will be welcome back at Harbour any time he wants after scoring three tries for the Hawks in his last game for the club before he moves to Southland.
Harbour dispatched Pirates at Hancock Park 52-10 - no surprises there except usually the Hawks use their enormous forward pack to grind their opponents down.
Harbour instead opted to spin the ball, particularly in the first half.
It rattled on the points and led 26-0 at the break.
Morris bagged the game's two opening tries and posted his hat-trick in the second spell.
When the weather closed in, Harbour reverted to type and forwards Ben Whale, Aiden Spence and Sione Misiloi saw plenty of action in the close quarters.
But Morris was the star - the centre stretched the defence whenever he got the ball.
His fend and strength certainly came in handy but it was vision which netted him his third.
He spotted an opportunity and came into first receiver then crashed through the defence.
Pirates had its moments. It actually had the better of the last 15 minutes, scoring two unconverted tries.
It strung some phases together and Pirates winger Clayton Buchanan scored a nice try and was one of the team's best players.
Lock Chris Morrissey was impressive as well and Hayden Fluery was industrious in the loose.
