Canterbury, Waikato and Bay of Plenty occupy the rungs above HBPB after three victories from just as many rounds.
HBPB tee off against Canterbury this morning and then will have to dig deep against Bay of Plenty in the afternoon in rounds five and six in what will, no doubt, be the defining stage of the premier amateur matchplay teams' tourney in the country.
Should the HBPB side do the unthinkable then it would set division two alight as semifinals loom in the five-day competition.
Southerden has maintained her enviable unbeaten run but others will have to come to the party big time to keep HBPB hopes alive of making the playoffs.
McDonald said last night they didn't take Tasman lightly but that sentiment will be truly put to the test today, twice over.
"They'll be pretty tough matches but we're all confident about it," said McDonald who is enjoying the No2 role.
The 22-year-old physiotherapist from Gisborne felt her putting was her forte yesterday although on day one she found the undulating, slick prime real estate hard to fathom.
"I was a bit tentative because I wasn't used to them, I guess. I've got my confidence as the days go on," says the plus-one handicapper from the Poverty Golf Club where professional Dave Keown has been mentoring her since she was 6.
Her maternal grandfather, Cliff Poole, introduced her to junior golf and the rest is history.
"It was fun," she said, enjoying the mental challenges the game offers.
After a loss on Monday, Wellington yesterday bounced back with two victories over Manawatu/Whanganui and Aorangi.
North Harbour, Canterbury, and BOP also jumped into Wellington's boat.
However, in the back of the minds of the playoff contenders is the threat Auckland pose.
The city slickers, who have won six tourneys in the past eight years, are posting equally big margins. They crushed Manawatu/Whanganui 5-0 in the morning before bursting host Northland's bubble with the same margin in the afternoon.
Men's interprovincial golf
It was a bitter-sweet day for every team on the opening day of the Men's Toro Interprovincials yesterday.
Hawke's Bay sat on a clustered leaderboard which left the blokes' matchplay wide open as players looked for any excuse to cool off on a stunning day at the Mangawhai Golf Club.
The Bay overwhelmed Poverty Bay/East Coast 4-1 — No 1 Ben Swinburne crushed Te Raumati Hawea 6&5, No 2 Mako Thompson gave Nathaniel Cassidy a 5 & 4 don't argue, No4 Tyson Tawera beat Kurtis Cortesi 3&2 and No 5 Russell Mitchell eclipsed Andrew Higham 2&1.
No 3 Adam Winter was the only loss, going down 2&1 to William Brown.
However, the Bay had to go hammer and tongs against Otago before the Southerners pipped them 3-2.
Swinburne halved with Fraser MacLachlan, Thompson came up shy, 1 down, to Brandon Hodgson, Winter halved with Duncan Croudis, Tawera came up 2&1 short against Michael Smith and Mitchell lost by the same margin to Chris Snow.
Otago, it seems, enjoyed their bye morning while the Bay would have had to take in
their stride the heat and humidity factor from playing two rounds.
The Bay are in second place on the ladder on six match wins, below leaders Southland who have registered half a win more.
Canterbury are third on 4.5 match wins while North Harbour and Poverty Bay follow, both on four wins each.
Hawke's Bay tee off against Southland from 8.40am today in round three and then lock horns with North Harbour from 1.10pm in round four.
Perhaps the most exciting victory of the day was Poverty Bay East Coast who defeated the in-form Southland team to light up the tournament.
They always seem to provide energy and a few great performances throughout the week.
In division one, Northland taking on defending champions Wellington in the morning to decide who are the early movers.
Auckland lead the standings on 6.5 match wins over Northland's 5.5.