India spinners Ravichandran Ashwin and Ravindra Jadeja claimed 16 wickets on a slow, turning track at Kanpur's Green Park Stadium to secure India's 197-run victory.
The 102-run stand between Mitchell Santner and Luke Ronchi on a fifth-day track, however, suggested that the local spinners were far from unplayable.
"To play the spin like we did for a period of time was good, and then there were moments where we lost concentration and made an error in judgement," Williamson told reporters.
"That comes down to facing very good bowlers but also having that control in your game that when you are in foreign conditions you are able to adjust and stick to a plan for a long period of time.
"There were moments we did that, but we need to do it for longer," he said.
New Zealand were 159 for one in their first innings but lost their last five wickets for seven runs to be bowled out for 262.
Santner impressed in defeat, claiming five wickets with his left-arm spin to go with scores of 32 and 71.
"He played outstandingly well. It's his first time in this part of the world playing test cricket and it was a great step in the right direction for his game," Williamson said of the 24-year-old all-rounder.
"We all know he has got the talent with bat and ball and in the field. To apply himself like he did and bowl a number of overs and be successful was very good against good players of spin.
"It was a huge positive for us. He'll look forward to the next one and I'm sure he's learned a lot from this experience," Williamson added.
(Editing by Ed Osmond)
