The White Ferns must now play perfect cricket if they wish to win this home World Cup.
Unfortunately for the hosts, as tonight's agonising defeat by South Africa showed, they seem some way short of reaching that standard.
South Africa's two-wicket win at Seddon Park means the knockout stages have started early for New Zealand, falling to a record of two victories from five matches.
It was so nearly a different story, after a stirring fightback from the bowlers enlivened a match that had looked dead.
With 15 overs to play, South Africa needed 70 runs and had eight wickets in hand. A revival sparked by Amelia Kerr's 3-50 then gave the White Ferns hope, but South Africa eventually sneaked to their target of 229 with three balls to spare.
The White Ferns can afford no more setbacks, either of their own making or from the weather. They must beat England at Eden Park on Sunday and Pakistan at Hagley Oval next weekend, with their semifinal hopes in that scenario still possibly dependent on net run rate.
Increasing their degree of difficulty, the best New Zealand can now hope for is likely a fourth-placed finish and an immediate rematch against Australia, who crushed their neighbours last weekend.
But based on tonight's evidence, a semifinal clash against South Africa will be no less daunting.
Their win made it four from four at this tournament and they dominated much of the match to earn their first World Cup win over New Zealand.
That domination was especially clear in the first innings, as the White Ferns squandered a fine knock of 93 off 101 balls from Sophie Devine to be dismissed for 228 in the 48th over.
Those extra overs left in the middle would prove costly, as would the lack of production once again from the hosts' middle and lower order.
After she won the toss, Devine built good partnerships of 81 with Amelia Kerr and 80 with Maddy Green, but those were the only significant contributions with the bat.
South Africa initially bowled straight and stuck to their plans, removing Suzie Bates cheaply as the hosts made a stuttering start.
Devine and Kerr eventually enjoyed some width and cashed in through multiples of four, before a double blow disrupted the progress.
First Kerr (42 from 58) missed a full toss to be trapped by Sune Luus, then Amy Satterthwaite was caught behind three balls into her stay.
The boundaries dried up as Devine looked to rebuild, advancing the total to 197-4 after 40 overs, but two balls later she was bowled by Ayabonga Khaka to spark a match-defining collapse.
New Zealand lost 6-30 in 44 balls once the soft underbelly of their lineup had been exposed, leaving their bowlers with just too much work.
Their defensive job began well, with a tight start from Jess Kerr and Hannah Rowe backed up by brilliant work from Katey Martin to run out Lizelle Lee.
South Africa crept to 33-1 after 10 overs before Laura Wolvaardt kickstarted the innings, putting together decent partnerships with Tazmin Brits (48 runs) and Luus (88).
But Amelia Kerr broke both of those stands, taking the key wicket of Wolvaardt (67 from 84), and when Rowe got Luus caught behind the chase assumed a different complexion.
South Africa were suddenly five down and sweating. The equation stood at 31 from 30 when Frankie Mackay got the dangerous Chloe Tryon caught at deep midwicket, and 18 from 18 when Mackay completed a high caught and bowled to snare the seventh South African wicket.
Devine bowled the penultimate over and struck with her second ball but, with pace available, turned to Mackay for the last and saw the spinner quickly dispatched as Marizanne Kapp (34 from 35) won the match.