Williamson's technical precision was exemplary as he built a platform before his exit at 153 after 33 overs.
He is perfecting the chip over the infield, and other strokes wouldn't have looked out of place on a snooker table, such was their adhesion to the McLean Park baize.
Mitchell McClenaghan took the crucial wickets of Virat Kohli and Mahendra Singh Dhoni on his way to four for 68 as he maintained the aggression demanded by captain Brendon McCullum.
"There will be times he travels, but we're happy as long as he attacks and tries to take wickets," McCullum said after the game.
"He bounced out four guys which is great, that's the plan we wanted."
Indian captain Dhoni said his team didn't pull well.
"We've got to master that, with two bouncers allowed every over. You can't pick and choose to leave them."
Chants of "Koh-li" and "Dho-ni" erupted as the pair bisected the field and dissected the attack in a fifth-wicket stand of 95.
Kohli made 123 off 110 balls, but the run of India winning each of the 12 times he has scored an ODI century while chasing came to an end.
If New Zealand erred anywhere it was bowling, but charging in against players with ODI averages of more than 50 is daunting.
Their fielding wasn't at fault. Led by the McCullum brothers, they chased like the ball was a $100 note in a hurricane.
Adam Milne often clocked in excess of 150km/h to take 1 for 40 before limping off after 7.3 overs with a side strain injury. He will have a MRI scan tomorrow.
"It's tough for Milney to get injured bowling at that pace, but his overs were still hostile which is exactly what we asked for," McCullum said.
"He'll be assessed tomorrow but it doesn't look great."
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