There had been little evidence of it during the first three ODIs, but swing made a belated appearance in the fourth ODI in Hamilton. It's a rare sight in white-ball cricket - so much so that a struggling Tim Southee finds himself out of New Zealand's ODI attack - and when it's there it spooks batting teams.
And when there's swing, who better than Trent Boult to exploit it?
Boult's 5 for 21, his seventh five-wicket haul in ODIs, blew away an India line-up lacking Virat Kohli, who has been rested from the remainder of this tour, helping skittle them out for 92, and helping New Zealand register their first win of the series.
Boult bowled his 10 overs in one allotment, unchanged, and by the time he was done India, at 55 for 8, had just gone past their lowest-ever ODI total. Despite causing such devastation in the opposition ranks, however, Boult didn't actually feel like this was his day and everything would go his way.
"Some days you do, but today really wasn't one of those days," Boult said in his post-match press conference. "I thought the wicket was pretty dry and it was actually quite slow, and yeah, couple of overs there, a little bit of swing, [which will] obviously keep you interested, but I suppose the modes of the dismissals there - a couple of caught-and-bowleds, which literally lobbed back to you, probably not how you traditionally see your wickets as an opening bowler.
"Yeah, it wasn't one of those days, to be honest, and it came out nicely and it was just nice to get a little bit of reward."
For all the modesty, even the two seemingly soft caught-and-bowleds were the result of Boult's two big weapons as a fast bowler: his awkward left-arm-over angle and his late swing back into the right-handers.
Both Rohit Sharma and the debutant Shubman Gill initially followed the angle across them, moving their front foot forward and across, as if in preparation for drives through the covers. Then, as the ball swung back in, they hurriedly pulled their front leg out of the way to make room for their bat to come down straight, but the panic of the late adjustment hardened their hands, causing them to pop the ball back to the bowler.
The same kind of delivery did for Kedar Jadhav too, the No. 6 batsman falling lbw, forced to play around a too-firmly-planted front pad.
It wasn't just Boult who swung the ball. Colin de Grandhomme did so too, picking up three wickets with his wobbly medium-pace, and Bhuvneshwar Kumar managed a couple of wickets in New Zealand's chase.
What makes a white cricket ball swing so much on some days, and so little on most other days in ODI cricket?
"I wish I had the answer, but no, I'm not sure," Boult said. "I think it's been a windy summer and wind kills the fast bowler, to be honest. Once it's a bit gusty, it eliminates the swing and the wicket dries out pretty quickly as well, and turns into a pretty good batting wicket, but yeah, the conditions were there today, and not just myself, the guys that backed each other up, they played their roles, and it was done nicely as a collective."
With Kohli not around, and MS Dhoni not fit, Boult's dismissals of both openers, by the eighth over of the innings, left an experimental India middle order facing a difficult situation.
"Yeah, it's the first time we've really got down into the middle order [in this series]," Boult said. "Obviously they've lost a classy player there, with their captain, but yeah, it's all about putting pressure on the top order, it's always been that kind of gameplan.
"It was nice to get through them and have a look at the middle order today. Very satisfying, we know we've got the gameplan, we know it works, and it was just about executing it, which I thought we did nicely today."