The Hawks also collect the Speight's Jug for winning the first round.
University pumped Kaikorai 62-17 and is in a rich vein of form.
Southern climbed one spot on the ladder with a 28-3 win against Green Island but still cannot catch the ball.
Dunedin was awful but still too good for Pirates, winning 58-13.
Zingari-Richmond showed more resistance this weekend but lost 41-32 to Alhambra-Union.
Harbour 36
Taieri 22
Harbour's dominance of territory and possession gradually wore Taieri into submission and the parting of the Speight's Challenge Shield after 17 successful defences and a reign two weeks shy of two years.
Taieri won the Challenge Shield by defeating University A 32-29 in a thrilling encounter on May 31, 2014, beginning the most successful sequence of defences.
Taieri scored a try through captain Kori Rupene in the opening minutes, but then lost a player to the sin bin, and Harbour capitalised with tries to Naulia Dawai and Joe Collins.
Although Taieri clawed back after being restored to 15 men to hold a 15-14 lead at the break, a further sin-binning offence meant it was back to 14 men for the start of the second half.
Again Harbour capitalised and regained the lead, defending it vigorously, while maintaining a stranglehold on territory and possession.
Taieri defended stoutly, forcing errors on the Harbour attack, but failed to counter when Harbour changed tactics and let its forwards run loose, netting a further two tries and shutting the gate on any chance Taieri had of retaining the Challenge Shield.
Not bad, considering Harbour finished the match with 13 men after two of its players were sin binned in the final minutes.
Southern 28
Green Island 3
If you love scrums then you were in for a treat at Bathgate Park.
Southern must have knocked the ball ahead perhaps 15 times.
The burly blokes up front were at risk of repetitive strain injury.
Green Island struggled to string any decent rugby together either and the game lacked continuity as a result.
The first 40 minutes were about as compelling as back-to-back episodes of Shortland Street.
It was tempting to cannibalise a body part or remove an eye.
Southern looked like coming right midway through he second spell but some more fumbling killed off the promise of an exciting final 20 minutes.
The last two minutes was pretty good, though.
The ball got toed through and Eroni Sotutu showed great gas to outpace the defence and catch up with the ball before it went dead.
Moments later, he ran around his marker and passed to his outside, where the hard-running Josh Gordon crashed into the defence.
The ever-present Adam Knight scooped up the ball from the ruck and delayed his pass to Axel Hohneck until the big lock had nothing more to do but jog the ball under the sticks.
Southern dominated the forward exchanges and really should have won by 50 points or so.
But the Magpies are adept at tripping themselves up at the moment.
Alhambra-Union 41
Zingari-Richmond 32
Alhambra-Union had too much endeavour in the backs but Zingari-Richmond had the better of the second half.
Alhambra-Union had built a comfortable 21-8 by halftime at the North Ground.
It stretched the gap to 28-8 when Alex Frood scored following an error from Zingari-Richmond at the lineout.
But the visiting side controlled possession and territory for most of the second spell, running in four tries in a 24-point haul.
The club suffered a 137-0 humbling at the hands of University A last weekend and it was good to see the team show some spirit.
Alhambra-Union made rare excursions into the Zingari 22m but managed to score points when it did.
Its effort in the second period was hampered by poor discipline which helped Zingari mount its comeback.
Alhambra-Union first five-eighth Rhys Morgan read play well and scored 26 points, while loosies Max Aitkenhead and Jacob Coghlan competed well at the breakdown.
Centre Noah Cooper had some nice touches in the middle of the field as well.
Tom Rowe and Mathew McCormick had good games in the pack for Zingari and veteran No8 Chris Bell was on hand to score two tries.
One of those was from a 20m rolling maul.
Zingari outscored Alhambra-Union five tries to four and will take heart from its much-improved performance.
University 62
Kaikorai 17
A hat trick of tries by New Zealand touch representative Taylor Haugh put the icing on the cake when the students scored nine tries to beat Kaikorai 62-17 at the University Oval.
The speedy left wing used his touch skills to outwit the defence three times in the second spell.
The students were aggressive and used their 40% of ball to break the first defensive line and used their speed to capitalise on this and score tries.
The rushed student defence made it difficult for the Kaikorai backs to break the game line.
University scored four first-half tries to lead 26-5 at the break and put the game out of Kaikorai's reach with two early second-half tries to lead 38-5.
First five-eighth Fletcher Smith, the general, kicked eight goals from 10 attempts to score 22 points to take his season's tally to 152.
Lock Josh Dickson and hooker Sam Sturgess were powerful in the tight and loose forwards Sione Teu and Dillon Hunt kept sustained pressure on Kaikorai.
Kaikorai was well beaten but not disgraced.
Its first-half try went through 12 phases.
Lock Willie Miller made seven clean lineout takes and flanker Blair Tweed was a strong defender.
Wing Matt Jones, Jayden Spence in the midfield and fullback Tony Ensor were the best backs.
Dunedin 58
Pirates 13
This was a game that never got off the ground and finished with a damp squib.
It was flooded with handling errors, erratic passing, innumerable penalties, non-existent tackling and frequent turnovers.
Pirates started reasonably well and dominated territory and should have been up by nine points if Kieran Fowler had brought his kicking boots but all it had to show for it was a lead of three.
Playing into the breeze, Dunedin then took over and had scored five tries by the break and the game was over as a contest.
Most of them were conceded because the Pirates side thought it was playing touch rugby.
The second half followed a sadly similar pattern but Pirates did score two tries when Dunedin tried to emulate the Pirates defensive pattern.
There was a collective sigh of relief when referee Rob Wells blew the whistle for fulltime.
He may need a lung transplant, the number of times he had to blow for penalties - 30-plus were given away.
For Dunedin, lock Mark Grieve Dunn was far and away the best player on the ground as he swatted tacklers away like flies and ate up the metres.
His many breaks led to tries.
Flanker Hame Toma was ever present at the breakdown and prop Sean Smith, in his 50th and blazer game, was powerful at scum time where the Sharks were dominant.
His replacement, Teague McElroy, the young colts prop, had an auspicious start to his prem career.
For Pirates, Sam Shuker was tidy at fullback and Fowler was dependable at first five-eighth.
Hooker Hamish Boult beavered away in a beaten pack.
But Pirates should spend the week on the tackle bags because, surprisingly, it is the key part of defence.
