McCullum's sparkling 224 guided New Zealand to a commanding 503 in their first innings before his bowlers reduced India to 130 for four by the end of the second day's play.
He said he had never imagined that the Kiwis would go past the 500-run mark after they were reduced to 30 for three in the morning session of the first day.
"I thought we will get 200-odd runs, because when you are 30/3 down you are thinking about small targets and getting a competitive score. Never did I think that after 30/3 in those conditions, we would end up getting 500 runs and for this batting line-up, I think that is a fine achievement," he said.
"We have bowlers to take 20 wickets if we give them enough runs and I think we have given them enough runs," said McCullum, after the second day's play was called off early due to bad light.
McCullum opined that the new ball was creating problems for the batsmen initially.
"The new ball is stopping a bit, when it is hard. We saw that with Ishant (Sharma) when the ball was changed in the morning and the pitch started to stop a little bit. Short catches in front of the wicket will become crucial as the game goes on," said the Kiwi skipper, agreeing with Murali Vijay's assertion that new ball is hurting batsmen of both teams.
"So, to get two wickets in the first over was outstanding, especially (Cheteshwar) Pujara's wicket, because he can bat for weeks. It's nice to get him pretty early. They had a nice partnership going in the end, but it means that we still have a hard ball tomorrow morning. There is a slightly earlier start and I am hoping for an overcast morning with some swing," he added.
Lanky Ishant Sharma was the pick of the Indian bowlers, taking six wickets for 134 runs in New Zealand first innings, and McCullum was full of praise for the medium pacer.
"Ishant bowled really well. He asked a lot of tough questions. His spell this morning was very long and every time we thought they will change the bowler, he kept handing in his cap and had another go at us. It was a deserving reward for him (six wickets). Some days you don't get wickets, like (Mohammed) Shami. I thought he bowled very well and didn't get the rewards. Ishant did a good job and kept coming at us, and he will be a tough proposition ahead in the series as well," said the Kiwi skipper.
But the real hero of the day was McCullum himself. He scored one run less than his previous Test best score of 225 runs, also scored against India at Hyderabad in 2010.
"Against some teams you perform better than other teams. So, yes, India is one team I have done well against. Batting at number five is suitable for me, with the ball not quite so new," he said.
"If we win the game, then I will consider it as one of my better efforts. But I am happy to contribute in a significant way, which was by building partnerships. We managed to keep creating partnerships after a tough start, so that is very satisfying," he added.
The major partnership of the innings was between McCullum and Kane Williamson (113) -- 221 runs for the fourth wicket -- lending the base for the tall total.
And McCullum has special words about Williamson, who scored 113.
"It was hard to rein myself in at times but batting with Kane was outstanding. He has a great temperament and has a great amount of maturity. He is experienced as well.
"We had a chat and he said that hundred is just a number. Our job at that time was not to get carried away and to keep batting and get good runs on the board. It was nice to tick off the milestone but yes we still had a job to do. So credit goes to Kane for his temperament and also his batting knowledge that he passed on to me," he said.
"A little disappointed that he got out, but his approach was right and rubbed off on me," McCullum signed off.
Image: Trent Boult of New Zealand (left) celebrates the dismissal of Cheteshwar Pujara
Photograph: Phil Walter/Getty Images
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