After being put into bat, New Zealand posted a mammoth 204-run target for India at the Eden Park. However, that didn't prove to be enough as the visitors comfortably chased down the total with six balls to spare and took a 1-0 lead in the five-match series.
"There are a lot of positives. It is hard to defend here and there was a bit of dew here. We knew we had to score over 200 with this being a used surface," Williamson said at the post-match presentation ceremony.
"Credit to India for the way they played," he added.
The New Zealand captain called on his bowlers to work on their wicket-taking skills and make sure they have breakthroughs at crucial junctures of the game.
"Taking pace off seemed to be working okay, but it was tough to execute because India put us under pressure constantly," he said.
"But we do need to find ways to pick up some wickets...It's important we improve in all areas in the next game," he added.
The two teams will now take on each other in the second T20I at the same venue on Sunday.