The Grizzlies have had a massive turnaround and won the first round, the Speight's Jug, with a resounding victory over Harbour at Miller Park on Saturday.
It won 30-10 and went clear at the top of the table.
In other results, Kaikorai continued to impress with a good win over Southern, while University easily beat Alhambra-Union and Taieri edged Dunedin.
University 54 Alhambra-Union 10
University got back on track with a convincing win against Alhambra-Union at the North Ground.
The students, who lost to Dunedin last week, were just too clinical for the home team, winning 54-10.
They had a bonus point in the bag by halftime when they led 26-10.
University's forward pack led the way, as the front row of Callum Hardie, Ricky Jackson and Angus Williams made metres with the ball in hand and were good on defence. No8 Henry Bell roamed well and was never far from the ball, as was captain Jack McHugh.
University scored three quick tries inside five minutes in the early stages of the second half. Winger Patrick Atkinson scored a brace. Taylor Haugh showed his speed to score his second try, speeding away from 40m out.
Atkinson completed his hat trick and brought up the half-century of points with a nice try from a well-timed Dale Jarden pass.
Alhambra-Union tried hard and scored a nice forwards' try in the first half off a lineout.
But it had very little territory or possession in the second half and was always on the back foot.
It made a decent number of tackles but University displayed some good support play which, in the end, broke the back of the Alhambra-Union side.
Fullback Levi Emery tried hard but was unable to get much going as the University defence was too clinical.
Green Island 30 Harbour 10
Green Island has emerged as the new front-runner thanks to a comprehensive victory against Harbour at Miller Park.
The Grizzlies made no race of the top-of-the-table match. It ran away with the game in the second half, winning 30-10 after leading 10-5 at the break.
The Hawks failed to fire and never got much going. It was not helped by the late withdrawal through injury of first five-eighth Logan Allen. Coach Ryan Nicholas stepped up and played in the pivot position for the first half and, although he played well, the side missed Allen.
It still scored the first try of the game, when hooker Austin Atiga got on the end of a lineout drive.
But Green Island held firm and shrugged off conceding the early try.
Prop Shane Fikken scored the side's first try, taking an inside ball from a drive near the line and Green Island went ahead when second five-eighth Raymond Nu'u went over after a nice break from Finn Strawbridge.
Green Island team totally dominated the second 40 minutes, led by strong-running No8 Dylan Nel. He was backed up by lock Sean Jansen and the rest of the forward pack never took a backward step.
Fikken got his second try while centre Yonhi Kim and winger Sunia Makasina also went over, to the thrill of the big home crowd.
Green Island got a roll on and just could not be stopped as the side was on the front foot throughout.
Harbour lost two players to yellow cards in the second half to bad tackles.
Replacement prop Abraham Pole and fullback Sam Porter both cooled their heels on the sidelines after a tip tackle and a head-high tackle.
Pole scored a try in the second half but Harbour was well off the pace throughout the match.
Nu'u looked good in the midfield for Green Island and the front row was strong for the home side.
Kaikorai 40 Southern 12
Strong defence, a dominant forward pack and the ability to dominate at the breakdown set Kaikorai up for victory, handing Southern a third consecutive defeat, in a tough encounter at Bathgate Park.
The home side had no answer for a rampant Kaikorai pack. Prop Sidney Fidow headed a strong tight five which kept Southern on the back foot and forced it into errors.
All too often Southern was left with nowhere to go with its possession. It become swamped in a sea of Kaikorai defenders, who were able to turn the ball over with relative ease.
Complementing Fidow in the engine room was lock Petelo Sinamoni, who was powerful on the burst. Blindside flanker Christian Lio-Willie was another standout in a dominant pack, with a high work rate both at the breakdown and at the lineout. He cleared no fewer than six clean takes from the lineout, and along with Sinamoni, Isimeli Tuivaga and Patrick McCurran disrupted the Southern throws.
Southern try-scoring machine Mackenzie Haugh was well covered, and for the first time this season, was kept tryless in a match. While the Southern pack seemed to be too reflective on past glory, opting for a scrum when awarded a penalty, forgetting that this was another area Kaikorai were dominating.
Haugh's Kaikorai counterpart Jordan McEntee perhaps took the bragging rights from the match, after he broke through a number of Southern defenders in a 35m burst to set second five-eighth George Thomas up for the bonus point try.
Taieri 15 Dunedin 7
Some compelling defence by Taieri proved the difference.
The Eels were forced to show their hand early as well.
Dunedin dominated the first 20 minutes. The Sharks spent huge stretches of time in the Taieri 22 only to be denied.
Dunedin was determined if nothing else. It turned down four kickable penalties in the first spell, which proved costly.
It inexplicably went to a lineout option but that mostly misfired.
Taieri made the home team pay with two tries, to establish a 12-point lead at the break.
The first went to prop Kieran O'Sullivan from a lineout drive and the second to midfielder Kori Rupene, who scored from a quick tap.
Taieri fullback Josh Casey kicked a penalty to extend the lead early in the second spell.
The game then reverted to type with Dunedin pounding away on the Taieri line with little or no reward.
Dunedin finally had some reward late, when the game was moved to top ground after lock Keegan Anderson suffered a suspected neck injury.
Replacement winger Riley Forbes got over in the corner. But it proved too little too late.
For Taieri, lock Ben Morris dominated the lineout and loose forward Bodie Hume led the defensive line.
Halfback Tatsuya Hamano was impressive on the clearance and Rupene and Matt Whaanga tackled everything that breathed.
Dunedin loosie Hame Toma was tireless and props Sepa Vaka and Teague McElroy were into everything and powerful at scrum time.
- ODT rugby writers