Kaikorai moved into the top four with a huge 87-7 win against the struggling Pirates outfit.
Southern made way for Kaikorai thanks to its 35-21 loss to University A.
While the students still look the team to beat this season, Southern pressured the defending champion and had its chances.
Taieri ground out an uninspiring 16-9 win against Alhambra-Union and Harbour held on to beat the much-improved Green Island 29-22.
Dunedin brushed aside Zingari-Richmond 57-26.
University 35
Southern 21
The Vic Cavanagh Memorial will remain in the University A trophy cabinet for another year after the student backline proved too slick for Southern.
However, the defending champion did not have it all its own way at the University Oval.
Southern trailed 21-6 at the break but first five-eighth Josh Ioane ran through an enormous gap to score.
The Magpies dominated the scrum and had put in another big heave to help set up the try.
That good work was undone by a laboured pass by Highlanders outside back Ryan Tongia.
Faasiu Fuitai picked it off and ran 50m to dot down under the post.
Tongia had not long been back on the field after he was yellow-carded late in the first half.
Southern second five-eighth Hemaua Samasoni made a crucial blunder as well.
Ioane had weaved his way around two defenders and passed to Samasoni.
He had a few yards to run and a dive would have completed the try, but he tried to get closer to the posts and was stripped by a desperate defender.
For all that, though, University deserved the win.
Centre Shae Tucker produced some early brilliance.
He scampered down the left flank and chipped ahead.
He regathered and then made a skilful backflip to Dillon Hunt who ran in the first of his two tries.
Southern got within seven points but hard-working No 8 Sione Teu barged over in injury time to deny the Magpies a bonus point.
Harbour 29
Green Island 22
Harbour made a positive start at Watson Park and opened the scoring with a try down the left wing.
Nick Corban provided the finish.
The ball had been put through plenty of hands before Corban got clear on the outside and he had an easy stroll in to the line.
Green Island replied with a penalty but Harbour swung back on to attack and scored two quick tries to lead 17-3.
The visiting side cut the gap before the break with hooker Ricky Hollamby crashing over.
Alex Barnsley knocked over the conversion.
The match lost some structure in the second spell with both sides bringing on some reserves.
It got messy but Harbour kept it together a little better and scored two more tries to lead 29-10.
But Green Island is not the pushover it once was, even with Highlanders prop Ross Geldenhuys standing on the sideline watching rather than playing.
The big guy scored three tries last week and looked to have itchy feet.
He would have been happy with the way his side finished, though.
Green Island nabbed two tries to grab a bonus point, the second on the stroke of fulltime.
Lock Ben Whale and openside flanker James Tomkinson were the best on display for Harbour, while Hollamby produced another quality performance for Green Island.
Taieri 16
Alhambra-Union 9
Taieri arrested its slide down the competition standings with a win against Alhambra-Union at the North Ground.
However, word from the venue was the Eels looked "pretty ordinary'' in a sloppy game dominated by mistakes.
Taieri gained an advantage whenever prop Aki Seiuli carried the ball and Willis Scott made some metres as well.
Seiuli actually switched to No 8 partway through the second half.
Alhambra-Union's line speed in defence was good but Seiuli is a hard man to stop and he made a difference.
The teams traded two penalties apiece in the opening 40 minutes.
The turning point came when Brodie Flannery scored shortly after the break.
Taieri got deep into Alhambra-Union territory.
The defence was solid but Taieri swung the ball to the left after bashing away at the right-hand corner.
Alhambra-Union just ran out of defenders and Flannery got around his marker and scored to the left of the post.
He notched up all of Taieri's 16 points.
His opposite, Rhys Morgan, knocked over three penalties to score all of Alhambra's points.
The most exciting part of the game was in the last five minutes when Alhambra-Union tried moving the ball but, quite fittingly, it knocked the ball on in the last act of the game.
Kaikorai 87
Pirates 7
No8 Paul Grant played a key role in Kaikorai's forward domination and this allowed the backs to unleash blistering attacks in dry conditions at Hancock Park.
Grant made eight clean lineout takes, ran strongly with the ball in hand and supported the back attacks.
He was given strong support by hooker Blair van der Voort and flanker Slade MacDowell as the Kaikorai forwards dominated the lineouts and scrums.
The backs moved the ball wide quickly to stretch the defence and the support play turned the opportunities into an exciting 13-try scoring spree.
Kaikorai scored five tries to lead 33-0 at the break and added eight more tries and 54 more points in the second spell.
The Pirates defence was more effective in the last 20 minutes when golden oldie scrums were played.
The star of the Kaikorai backline was right wing Matt Jones who always looked for work and scored three tries and kicked six conversions to score 27 of Kaikorai's points.
Fellow winger Eti Slater also scored a hat trick of tries.
First five-eighth Ben Miller scored a try and kicked five conversions while Jayden Spence and Danny van der Voort were solid in the midfield.
The best Pirates players were first five-eighth Keiran Fowler and loose forwards Daniel Mulvena and Will Ward.
Dunedin 57
Zingari-Richmond 26
Dunedin took full toll on a lacklustre start to the game by Zingari-Richmond in a classic game of two halves at Montecillo.
The first of Dunedin's seven first-half tries was scored against a team of 13, with two of the home side players laying cast on the ground, having banged heads at a breakdown in the opening minutes.
This was followed by wing Charlie McCartin scoring the first of his two tries.
The remaining six first-half tries all came as a result of inept defence, with Dunedin's midfield back pair of Leroy van Dam and Fapene Popoali'i exploiting the gaps and defensive lapses with ease, and a Dunedin pack permitted to run rampantLineouts will be something to work on for Zingari-Richmond, as its throws often went into midfield and into the hands of a waiting Dunedin backline.
For Dunedin, Mark Grieve-Dunn was influential in ball retention, and proved a factor in general play along with prop Sean Smith and No8 Jamie Mowat.
The harsh realities of premier rugby echoed by coach Andrew Melville at halftime gave witness to a more committed Zingari-Richmond in the second half.
Wing Inoke Naivalulevu and fullback Chris McNoe displayed their game-breaking abilities, while lock Phillip Kinraid and prop Liam Sharples featured in the close exchanges.
