Flying winger Tom Davie used his blistering speed to score two second-half tries to take his tally for the season to eight.
University A scored six tries to beat Green Island 39-14 and extend its lead in the Gallaway Trophy to 11 points after 10 of the 14 rounds before the semifinals.
But behind the students is a log jam, with seven teams capable of filling the last three spots.
Just nine points separate second-placed Pirates and eighth-placed Harbour.
Kaikorai caused the other upset when it outplayed Pirates 35-13 to move into fifth place.
The return of Highlanders Alando Soakai and Fetu'u Vainikolo has injected confidence into a Kaikorai team that is now firing on all cylinders.
Luke Reihana kicked 13 points for Alhambra-Union in a 38-38 draw with Harbour to become the first player to reach 100 points this season.
The leading scorers are: Luke Reihana (Alhambra-Union) 108, Chris Noakes (University A) 97, Craig Sneddon (Harbour) 80, Lewis Hancock (Southern) 69, Cam Rutherford (Kaikorai) 68, Kieran Fowler (Pirates) 55, Hayden Parker (Taieri) 49, Glenn Dickson (Pirates) 46, Louis Tili (Dunedin) 45, Peter Breen (Alhambra-Union) 43, Tom Davie (Taieri) 40, Paula Kinikinilau (Alhambra-Union) 40, Hoani Matenga (University A) 40.
The Gallaway Trophy points after nine rounds are: University A 42, Pirates 31, Alhambra-Union 29, Southern 28, Kaikorai 27, Taieri 26, Dunedin 26, Harbour 22, Green Island 8, Zingari-Richmond 0.
Taieri 30 Dunedin 22
Captain Charlie O'Connell led by example and was the catalyst for Taieri's upset win at Kettle Park.
Dunedin took the lead for the first time with 10 minutes left when flanker Gareth Evans grabbed the ball from a lineout inside the Taieri half and the forwards drove toward the line.
First five-eighth Shaan Davis cut through untouched to score under the bar and Dunedin led 22-20.
But O'Connell had played aggressively throughout the game and was not going to meekly surrender.
He rallied the troops and Taieri attacked inside the Dunedin half and first five-eighth Andrew Reid kicked his second penalty goal and Taieri led by a point.
Shortly after, from a Kaikorai clearing kick, O'Connell tapped the ball into the hands of winger Tom Davie, who outpaced the defence to score his second try and make the game secure.
O'Connell was the player of the game with his strong tackling, breaks with the ball in hand and his skill at the breakdown.
He was backed by fellow loose forwards Jeremy Corliss and Nathan Young.
Taieri had a more enterprising backline and was effective on the counter-attack when the ball was kicked back by Dunedin.
Carne Parata was a sniping halfback and centre Ryan Shortland always looked dangerous.
The Dunedin front row of Kelsey Miller, Will Henry and David Smart was dominant and pushed Taieri back in the scrum, while Evans was a lively flanker.
Halfback Fraser Lau was the best Dunedin back with his long passing and skilled kicks over the top and his covering.
Michael Walding was able to breach the advantage line in the midfield and was an effective defender.
Taieri 30 (Tom Davie 2, Ryan Shortland, Kurt Webster tries; Andrew Reid 2 conversions, 2 penalty goals), Dunedin 22 (Louis Tili, Shaan Davis, Will Henry tries; Tili 2 conversions, penalty goal).
Halftime: Taieri 15-10.
Referee: Doug Rodgers.
Southern 43 Zingari-Richmond 5
Veteran prop Warren Moffat was part of a front row that played a key role in Southern's win over Zingari-Richmond at Montecillo.
Moffat was strong on the burst and with the pick and go and was backed by former All Black Kees Meeuws and Ean Griffiths in the front row.
Southern did the basics efficiently and locks Sam Gavigan and James Stevenson supplied clean ball from the lineout.
No 8 Sam Crompton was dangerous with the ball and was able to breach the advantage line.
Fullback Hamish Buick was effective on the counterattack and new Otago signing Joe Hill showed some deft touches at centre and used his speed to score a try.
He created opportunities for flying winger Greg Zampach, who scored a hat trick of tries.
Southern led 24-0 at the break, but Zingari-Richmond kept up an aggressive defence in the second spell with captain and No 8 Chris Bell leading the way.
Lock Brady Carmichael had a strong game and halfback Troy England and fullback Nathan Napier were the best of the backs.
Southern 43 (Greg Zampach 3, Hamish Buick, Joe Hill, Sam Crompton, Ean Griffiths tries; Lewis Hancock 4 conversions), Zingari-Richmond 5 (Steven Bird try).
Halftime: Southern 24-0.
Referee: Ben O'Keefe.
University A 39 Green Island 14
Midfield back Andrew Parata was able to break the advantage line and played a key role in University A's six-try win over Green Island at the University Oval.
It was his ability to stand in the tackle that enabled the student backline to run freely and create opportunities out wide.
Fullback Matt Faddes showed his class when joining the line and displayed electrifying speed to score two tries.
A big factor in University A's domination of the game was the aggressive loose forward trio of Paul Grant, Hoani Matenga and Brad Cameron.
Grant was outstanding with his hand to hand passing and support play and Matenga had a high work rate and was rewarded with two tries.
The students also gained a monopoly of ball in the lineout through the work of lock Logan Collins.
Good tackling by Green Island No 8 Guy Archibald and the honest toiling of Frankie Elisara in the front row held University to a 21-14 lead at the break.
Green Island had a well organised defence with Sam Erepia excelling in the midfield.
First five-eighth Alex Davies gained large chunks of territory with his punting but he had few opportunities on attack because he received the ball going backwards.
University A 39 (Matt Faddes 2, Hoani Matenga 2, Andrew Parata, Alby Herron tries; Tom Halse 3 conversions, penalty goal), Green Island 14 (Chris O'Neill, Josh Beer tries; Alex Davies 2 conversions).
Halftime: University A 21-14.
Referee: Jeff Grubb.
Kaikorai 35 Pirates 13
Alando Soakai and Fetu'u Vainikolo proved inspirational forces for Kaikorai as it continued its late run towards a semifinal spot with a big win over Pirates at Hancock Park.
The sides appeared evenly matched, with each giving the ball plenty of air in the opening exchanges.
This led to Kaikorai enjoying a decisive territorial advantage as mistakes crept into the Pirates side.
Kaikorai halfback Tomasi Palu capitalised on some Pirates indecision when he opted for a quick tap of the ball at a penalty and ran in 15m virtually unopposed.
Two further tries in quick succession, one by winger Richard Cowley and the other by flanker Alando Soakai, also had Kaikorai exposing weakness in the Pirates defence.
Pirates then regrouped and tightened its game up in the second half but, despite dominating territory, was unable to turn this into points until the 65th minute, when Marshall Suckling worked his magic and ran from 40m out to score.
Injuries took a toll on Pirates, but Kaikorai would be buoyant after such a good performance against a side placed second in the competition.
Kaikorai 35 (Tomasi Palu, Richard Cowley, Alando Soakai, Jim Stevenson tries; Cam Rutherford 3 conversions, 3 penalty goals), Pirates 13 (Marshall Suckling try; Suckling conversion, Kieran Fowler 2 penalty goals).
Halftime: Kaikorai 24-6.
Referee: Ross Barnett.
Harbour 38 Alhambra-Union 38
Harbour was just denied in a nine-try thriller against Alhambra-Union at Watson Park.
Harbour, outplayed in the first half, had the better of the second and seemed likely to win when it launched a furious assault on the Alhambra-Union line in the final minutes.
But, after battering its way almost to the line with a series of pick-and-goes, the ball was knocked on and Alhambra-Union cleared to touch to end the game.
It was a fair result after Alhambra-Union scored four tries in the first half in which the dominant figure was strapping centre Paula Kinikinilau.
He scored two tries with his strength, speed and support and set up another for the loose-head prop, Ben Pereira.
Harbour tightened up in the second spell and played the game more through its forwards in which its front row of Ben Nolan, Peter Mirrielees and Pieter van der Merwe was dominant at scrum time.
Craig Sneddon kicked seven goals from eight attempts for Harbour to contribute 18 points, Ben Marshall was steady at second five-eighth and Johnny Legg was a class act at halfback.
The pack played particularly well as a unit in the second half with flanker Eben Joubert becoming increasingly prominent.
Kinikinilau was the player of the first half but had few opportunities in the second, Luke Reihana kicked six from seven and was classy in midfield and new winger Desma Liania showed plenty of pace.
Pereira was the pick of the Alhambra-Union forwards and was outstanding in the tight-loose.
Harbour 38 (George Folau, Ben Marshall, Johnny Legg, Sam Ready tries; Craig Sneddon 3 conversions, 4 penalty goals), Alhambra-Union 38 (Paula Kinikinilau 2, Jone Puamau, Mitch Ewen, Ben Pereira tries; Luke Reihana 5 conversions, penalty goal).
Halftime: Alhambra-Union 28-21.
Referee: Tim Baker.
