At 117 for one that view seemed the case. Overs weren't an issue and it seemed South Africa would have made the ideal start.
De Villiers: 'The toughest conditions I've ever played in'
Then they lost four wickets for nine in the space of 14 balls and it all changed.
Want to find a scapegoat for the tumble? Try opener Quinton de Kock, the man of the match who had got to 69 and seemed set to steer South Africa across the line.
He casually pulled at a short ball from Trent Boult to be caught at mid wicket.
Faf du Plessis had gone lbw to legspinner Ish Sodhi in the over beforehand.
Then JP Duminy chipped a return catch back to Southee, Farhaan Behardien was bowled by a beauty next delivery and it was all on.
Chris Morris hit a run-a-ball 16 before holing out to long off leaving de Villiers the remaining batting hope.
South Africa needed 81 off 11 overs, 59 off eight, 50 off seven, 46 off six and things had got seriously crunchy with Morris' dismissal.
Sodhi did a good job and it became 22 of the last two overs.
When Andile Phehlukwayo clouted the second ball of the laste over for six to long on it seemed to have decided it.
But Southee dug deep and it was left to de Villiers to settle it.
For the second time in as many matches, New Zealand's batting was undone largely by one South African bowler.
New Zealand were in early trouble and were unable to get a permanent foothold in the innings.
The final unbroken 51-run stand off just 23 balls between Colin de Grandhomme and Southee put some much needed oomph into the innings, 25 coming from the final over, by tall seamer Morris.
At Eden Park in the sole T20 international on Friday night, legspinner Imran Tahir shot through the bottom half of New Zealand's innings, taking five wickets in 15 balls as the hosts were rolled for 107.
The early damage that night was done by Morris, and he was the main man today as he had New Zealand wobbling at 82 for four, all four wickets in his back pocket.
Neil Broom's dismissal meant the 29-year-old from Pretoria had tour figures of 8-1-34-6 at that point.
Kane Williamson stood firm through the troubles, clearly a cut above his team mates.
He passed 50 for the 28th time in ODIs off 48 balls and played resourcefully in testing conditions where the ball frequently held up on a surface which has had its share of water in the last week.
There wasn't much else to offer, save the ebullient late hitting of de Grandhomme and Southee.
When New Zealand sift through the batting problems today they may start with Latham, who is in a trough.
Strange to think that on Boxing Day he was making a 121-ball 137 against Bangladesh.
Since then Latham has made scores of 22 (35 balls), 4 (eight), 7 (14), 0 (11) and 0 (13) in ODIs. That's 33 runs off 81 balls.
The second ODI, a day game, is at Christchurch's Hagley Oval on Wednesday.
