Poor Sri Lanka collapse to 8-4 early before being bowled out for 102
Brilliant Boult takes 4-13
Phillips, dropped on 12 and 45, brings up stunning century off 61 balls before falling for 104
NZ recover from 15-3 to post 167-7
Group 1 leaders NZ now on five points, two clear of England, Ireland and Australia
That is just about it from us for today, we'll be back tomorrow for another big day of T20 World Cup action as Group 2 takes centre stage.
Join us again tomorrow with India v South Africa among the three games taking place. We'll see you then!
More from Kane Williamson on TMS: "There’s a lot of cricket left so for us it's about focusing on the next game. As we have seen it doesn’t matter who you play, anyone can beat anyone. There’s match-winners throughout.
"It’s very much about focusing on our plans, our skills, and making adjustments. We are looking forward to the next one.... There are match winners in our team throughout, as in other sides, so it's really trying to put performances together."
Sri Lanka captain Dasun Shanaka: "We started really well, especially in the first 10 overs we bowled really well. Glenn Phillips played an outstanding knock but there are areas we can improve, especially in the fielding, we dropped a few catches.
"Chasing 160 is always a tough ask with their bowling attack. Trent Boult and Tim Southee bowled really well so credit to them."
On the chase:"There is a way to chase down big totals and in the first couple of overs we have to give ourselves a chance. We never gone settled, we failed. Wickets fell at regular intervals."
On rest of the tournament:"If we can finish with a couple of wins then we have a chance of qualifying so we're looking forward to those games."
More from Kane Williamson on TMS: "You always see that the run rate is always important. It's interesting, when you come to these tournaments anyone can beat anyone.
"Conditions suit one team more than the other. You have to try and think on your feet. It’s nice we were able to do that today."
New Zealand captain Kane Williamson, speaking to Test Match Special: "If we look at today’s performance it was remarkable on a very difficult surface. To see someone like Glenn change the pressure and put it back on the opposition and get a hundred was remarkable.
"One of the best knocks I’ve seen for sure. Conditions change all the time, and you play against different opposition. To be under pressure and be able to get out of that position and put together a good performance off the back of Glenn’s unbelievable knock was a good feeling for sure."
After Phillips' heroics with the bat, New Zealand's bowlers quickly put Sri Lanka in big trouble and all-but ended the contest inside the first four overs of the chase.
More from Glenn Phillips on getting cramp:"I really wanted to stop that two, a bit of a silly decision in hindsight and it felt like there was a sniper in the ground. The boys just said to sit off for the rest of it."
On scoring a century at a World Cup: "It's absolutely indescribable. I've really been trying to stick to my process and use that as a form of win for me. I was more happy with my process than anything today.
On the bowlers: "They swung it up front and then the slower balls they bowled with popping and holding. Getting a few wickets early on is crucial when you're defending a total. The bowling, the fielding, we were high energy... it was exceptional all round."
Player of the match, New Zealand's Glenn Phillips: "Me and Daryl [Mitchell] were clear that we wanted to carry on being as positive as possible (at 15-3).
"On a pitch like that it was difficult to hit the slower balls so, for us, it was getting through and getting to a competitive total. At the end, I think we were a little bit ahead of par.
"When it comes to cricket, I try to entertain as much as possible - whether that is for good or bad but thankfully today was on the good end of things. The way the rets of the boys played, the way the bowlers bowled and in the field, it was an incredible effort all round."
Stuart Clark
Former Australia fast bowler on Test Match Special
It is an absolutely thrashing of the highest order for New Zealand over Sri Lanka. They were in the game at the start but the innings of Glenn Phillips really took it away.
The opening spell of Trent Boult and Tim Southee put them on the back foot from the off. Unfortunately the game was over for the Sri Lankans very early.
Job done for New Zealand. From 15-3 early in their innings, they have fought back brilliantly. Glenn Phillips led the way, making the most of his good luck after being dropped twice, to hit his second T20 international hundred.
That helped the Black Caps to 167-7 and Tim Southee and Trent Boult quickly reduced Sri Lanka to 8-4 in the reply, ensuring they never came close to chasing it down.
In terms of qualification, New Zealand are almost there. A win over England would seal it. Even if they lose one of their last two matches, their net run-rate should be able to get them into the semis now.
Kumara st Conway b Sodhi 4 (SL 102 all out)
Lahiru Kumara comes charging down the track to Ish Sodhi, misses with a big swing and Devon Conway does the rest. A comprehensive win for New Zealand!
Into the final over we go, the result has been settled for a while. New Zealand have been very impressive with the ball.
Stuart Clark
Former Australia fast bowler on Test Match Special
Rajitha is getting behind it. Showing commitment. That's what you want to see.
Cheers from the Sri Lankans in the crowd as a wide from Tim Southee takes them to 100. You have to take what you can get in this game!
Two overs to go, Sri Lanka need one more to get to three figures - these things make a difference psychologically - and New Zealand need one more wicket to wrap this game up.
Stuart Clark
Former Australia fast bowler on Test Match Special
He rocks back and bang. Good shot from Kumara.
A drag down from Ish Sodhi and number 11 Lahiru Kumara gets stuck into it, pulling away in front of square for four.
Andrew Moore
BBC Test Match Special
The beauty of Trent Boult is the variations. You can't quite tell when he bowls that off-speed ball.
He's a Glenn Phillips hundred away from man of the match.
Stuart Clark
Former Australia fast bowler on Test Match Special
Shanaka has been the shining light in the Sri Lankan innings. He's really fought hard.
Shanaka c Mitchell b Boult 35 (SL 93-9)
A wonderful final over from Trent Boult ends with his fourth wicket!
After three dots in a row, Dasun Shanaka tries to pull the bouncer into the stands, top-edges it and holes out to Daryl Mitchell at deep square.
Boult ends with career-best T20 international figures of 4-13!