Karunaratne led from the front with a crafty 122 as Sri Lanka chased down 268 with relative ease, bettering the previous record chase in this venue, 99, by some margin.
"After losing the toss, the bowlers did a great job to restrict them to 249. When the ball was hard, it was turning and bouncing, but once it got old, batting became easier," said Man of the Match Karunaratne in the post-match presentation ceremony.
The skipper said that he and Lahiru Thirimanne had discussed that they needed to stay in the middle as long as possible in the fourth innings. The duo eventually stitched a 161-run opening stand to lay the foundation for a Sri Lanka win with Thirimanne contributing a valuable 64.
"It was not easy to bat in the fourth innings. We wanted a good partnership and that's what me and Thirimanne discussed. Once you get set, you got to finish the job.
"We saw (Ross) Taylor and (B.J.) Watling bat on this pitch. So we were saying it's not too dangerous, we just have to spend some time in the middle," Karunaratne said.
New Zealand captain Kane Williamson, on the other hand, said that the visitors probably lost the game in the bowling department.
"We probably batted reasonably well and didn't bowl well enough. There are a lot of positives from the game for us. The rankings and the points are secondary to the quality of cricket that we want to play. This Test match wasn't our best performance, but Sri Lanka played really well and deserved to win," Williamson said.
( With inputs from IANS )