That win has seen the students move back into the top four at Dunedin's expense. The Sharks suffered a 25-17 loss to Southern and their season is now poised precariously.
Harbour also made a move. Its comprehensive 50-22 win over Alhambra Union helped it leapfrog Southern at the top of the table. Both sides have the same points (64) but Harbour beat Southern earlier in the competition and has a better points differential.
Zingari Richmond posted six second half tries to run away with a 51-30 win over Pirates, while Kaikorai dispatched Green Island 44-12.
University A 29
Taieri 28
A second half resurgence saw University A turn the tables on Taieri at the University Oval in a thrilling clash for the Paul Sapsford Memorial Trophy.
The term ''game of two halves'' could fit nicely. Taieri dominated territory and possession for the greater part of the first half.
But with time showing to end the first half and their side trailing 22-6, the University forwards found their mojo, scoring through flanker Dillon Hunt from a maul 5m out, to reduced the deficit to 22-11 at the break.
Earlier, Taieri first five eighth Josh Casey brought up 200 points for the season with a superb try, typical of his ability to support and score from broken play.
Taieri played a controlled game early in the second half, exposing some defensive lapses in University, but was only able to convert two penalties.
Despite losing a player to the bin, and trailing 28-11 with half an hour remaining, the students clawed their way back into the game, exposing gaps in and around Taieri's defensive line.
That led to a sensational try to winger Gavin Stark, who wrong footed immediate defenders and broke through six tackles to start a scoring blitz.
Tries to Matt Faddes and Sam McLachlan followed, and with University A under the spell of white line fever, a penalty on the stroke of fulltime secured the victory.
Southern 25
Dunedin 17
Southern played with the wind at its back in the first half at Kettle Park but, to a degree, squandered that advantage and led by only six at the break.
First fives Bryce Hosie and Greg Dyer traded early penalties, before Southern started exerting territorial pressure. The Magpies were rewarded with a try after 15 minutes, after a series of pick and goes that led to prop Tom Scanlan crashing over close to the posts.
This fired up Dunedin, which dominated the next 15 minutes and scored in similar style, when flanker Hame Toma levelled the scores.
Dunedin conceded two late penalties to go into the half trailing by six. The game was transferred to the top ground early in the second spell after a spectator collapsed and an ambulance was called.
Southern won the game in the first 20 minutes of the half by playing into the wind rugby and holding the ball for long periods.
The Magpies could not score tries because of good Dunedin defence, but they were awarded plenty of penalties and kicked four to win the game.
Dunedin was not helped by having two players in the bin at various times, but scored the only try of the second half, when centre Tumua Ioane brushed off a few tackles to put Trent Renata under the bar.
That got the Sharks within five but they conceded a late penalty to miss the bonus point.
Prop Mike Mataafa was Southern's best player. Mika Mafi and Dan Baxter were conspicuous in the loose but, apart from Bryce Hosie, Southern was lethargic out wide.
Halfback Tyrone Davies was Dunedin's best, and Donald Brighouse, Mark Grieve Dunn and Danny Underwood stood out in the pack.
Zingari Richmond 51
Pirates 30
Pirates kept falling off tackles and Zingari Richmond kept scoring tries - eight in all and six of them in the second half.
The game was in the balance at the break with the home side leading 17-15 at Montecillo.
Second five eighth Lachie Moore had a productive second half. His early bust led prop Chris Preddy finishing off in the left corner.
Moore was the beneficiary of some weak tackling shortly after, swatting off some feeble attempts to score following a quickly taken tap penalty.
The Colours also had their moments on defence. Pirates scored five tries, and when Motu Hutch crashed over following some good lead up work, the visiting side trailed just 29-20.
But Zingari Richmond replied immediately. That man Moore bust through again and offloaded to centre Taylor Fiddes, who still had plenty of work to do to add to his first half try.
Winger Stephen Scoles scored twice and hard working loose forward Chris Bell also dotted down twice in the game.
Pirates was solid up front. Lock Jared Williams and prop Hisa Sasagi were among Pirates' best, and fullback Craig Sneddon made some incisive runs but also threw some terrible passes.
Harbour 50
Alhambra Union 22
Dynamic hooker Sekonaia T Pole scored the first two tries and played a key role in Harbour's eight try win at the North Ground.
Both his tries came after a series of driving thrusts by the Harbour pack. This was a feature of the Harbour game, as the forwards burst through the defence and opened up gaps that were exploited by the backs.
The powerful Harbour scrum kept pushing Alhambra Union off the ball in the set pieces. Props Pete Mirrielees and Pingi Tala'apitaga joined T Pole in a powerful front row.
No 8 Charles Elton was the workhorse in the Harbour pack. He made ground off the back of the scrum and made six clean takes in the lineout. Lock Elioti Tonga collected five lineouts, including two off Alhambra Union throws.
Centre Aleki Morris scored two tries and was the best Harbour back. Tala Fagasoaia and Sio Tomkinson were an efficient inside back combination.
Harbour had its foot on the throttle in the first half and scored five tries to lead 33-3 at the break. But its play became disjointed in the second spell when Alhambra Union applied more pressure. It was only in the last 15 minutes that Harbour lifted its game to score three more tries.
The best players for Alhambra Union were centre Tili Puloka and No 8 Lance Barbarich.
Kaikorai 44
Green Island 12
It was groundhog day for Green Island in the Ken St Clair Newman Memorial at Bishopscourt.
Kaikorai was much more potent with the ball and dominated the match, as the scoreline suggests.
But Green Island really is its own worst enemy at times. Whenever it appeared to be making some progress or an opportunity was opening up, Green Island would come up with a fumble or give away a silly penalty.
It had plenty of possession in the opening half but Kaikorai played the game in the right half.
Kaikorai fullback Tony Ensor was sharp, and centre Danny van der Voort was a handful. Up front, props George Hendry and Jonah Aione set a solid base.
No 8 Nathan Hull exploited his side's scrum dominance. He made some damaging runs and managed to score twice, once from the boot of the scrum.
Green Island's Jackson Hemopo scored the try of the game. He handled the ball twice before displaying enormous strength to get across the line in heavy traffic.
