India could get only only one wicket in the morning session and bowled 26 wicket-less overs in the second session.
"Their (Williamson-Latham) discipline (was key). They stuck to their game plans and when the Indian bowlers missed we jumped all over it. I thought the way they rotated the strike with that left and right-hand combination throughout the partnership was crucial," McMillan said at the press conference after the second day's play at the Green Park.
The former New Zealand all-rounder said Kiwi batsmen have done a lot work to counter the spin but in their own individual style.
"We've done a lot of work in terms of using the feet and getting deep in the crease. They are all key things to playing spin well. You watch the best players of spin around the world and they don't get caught on the crease, they are either forward or back. All our guys have done a lot of work on that and everyone does it differently," he said.
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(REOPENS DEL 56)
"That's part of playing in India. We are confronted by two very good spinners who know the conditions well and are going to challenge you at different times. Mental (focus) plays a big part, not getting flustered, being comfortable in those conditions and being comfortable with the ball beating the outside edge and not letting that worry you," MacMillan said.
McMillan also said that Latham was lucky when his shot that bounced off his feet hit close in fielder KL Rahul's helmet grill.
"I haven't spoken to him, but obviously he has hit it into his foot and it's bounced up nicely. Then the ball has ended up hitting the grill which means he is not out. A bit of luck on both sides. A bit of luck that he has hit it into his foot and it is a catch, and then a bit of luck from our side that it ended up touching the close fieldsman's grill. We were happy with that and the way it played out," he said.
"Well he has one of the shortest run-ups in world cricket so it is never going to take long for him to get through his overs. As a batsman it is important you are not rushed and you take your time so you are ready to face in your own time. That can be difficult when someone has such a short run-up, but I thought the guys did that well," he said.
He also said the rain-break was frustrating and it was difficult to say at this stage of the match which team's bowling combination was better.