West Indies 215 for 8 (Brathwaite 66, Southee 2-34) trail New Zealand 373 (Raval 84, de Grandhomme 58, Gabriel 4-119) by 158 runs
Trent Boult and Tim Southee pillaged 61 runs together at the start of the day, then claimed two wickets apiece, and held one spectacular catch each, as they set off and then perpetuated West Indies' dramatic decline on a rain-interrupted day.
By stumps, New Zealand had a stranglehold on the Test. Their opposition, eight down, and still 158 runs short of the hosts' 373, were facing a long climb back into contention. Only Kraigg Brathwaite made a substantial score, hitting 66 off 116 deliveries while several batsmen made promising starts and perished around him. Having ended the first day with so much momentum, and even begun day two with a wicket in the first over, West Indies were guilty of failing to apply themselves on a pitch that - while lively - was not the challenge their scoreline made it seem.
It was in the eighth over of the day, with New Zealand's score on 312 for 9, that Tim and Trent's day-two adventure began. Getting off the mark with an enterprising uppercut for four over the slips off Shannon Gabriel, Boult tried the shot again next over, and this time fetched six for it. Before long he and Southee were in the middle of a full-scale blitz, Boult hitting five fours and two sixes in his 27-ball 37 not out, while Southee cracked 31 off 39, hitting two leg-side sixes and a four of his own. They were aided by Seddon Park's modest dimensions, as even mis-hits proved a challenge to West Indies' fielders. But there was spunk to go with the luck - Boult backing off awkwardly against Miguel Cummins at one stage, only to reach out and blast past point a ball that might have shaved the top of off stump.
New Zealand had begun the day in danger of not making it to 300, but thanks largely to their No. 10 and No. 11, 87 runs were added to the overnight score. Kemar Roach, who dismissed Neil Wagner third ball of the day (thanks to a flying catch at gully by Shai Hope) claimed the final wicket to finish with figures of 3 for 58, while Gabriel, who also took a day-two wicket, ended with 4 for 119.
It was in the field, and with the ball, however, that Boult and Southee really left their mark on this Test. Gaining more bounce and carry from the surface than West Indies had managed (though it is possible the pitch had quickened up), they began beating edges almost immediately. Southee took the wicket of Kieran Powell in the first over, having the batsman caught behind for zero. Boult took longer to make his breakthrough, dismissing the spirited Shimron Hetmyer with a sublime return catch, leaping to his left.
Having tottered to 46 for 2, West Indies then seemed to be regaining their composure while Brathwaite and Hope were at the crease, but when play resumed after a rain delay of almost two hours, more wickets were in store. Hope nicked one to the slips off Southee soon after play re-started, then Roston Chase and Sunil Ambris both departed in quick succession - the latter treading on his stumps to the bowling of Boult, as he played a back-foot shot on the leg side. This was the second time in three innings that Ambris was out hit wicket.
When Southee caught Brathwaite spectacularly on the juggle soon after - the ball hitting the tips of his outstretch hands at short cover, only to bounce out and then be re-taken just before it hit the turf behind him - West Indies had lost four wickets for 45 runs. Brathwaite had been the player holding the innings together, keeping out the good balls and finding boundaries behind the wicket - though he did have some luck when he was dropped off Boult in the slips, on 14. He left West Indies at 135 for 6 - in danger of not making 200. Thankfully, for the visitors, Shane Dowrich struck a belligerent 35 before top-edging a pull off Neil Wagner, and debutant Raymon Reifer moved to an unbeaten 22 by stumps.
Southee returned New Zealand's best figures of the day, his two wickets only costing him 34 runs. Colin de Grandhomme and Wagner also had two wickets to their name. Mitchell Santner's left-arm spin was not required.
Andrew Fidel Fernando is ESPNcricinfo's Sri Lanka correspondent. @andrewffernando