The visitors were bowled out for 152 runs on day one and England reached 113/3 in reply at stumps.
"I was disappointed to find out that we lost the toss and then we got lucky with overhead conditions," said Broad.
"But it wasn't just about the conditions. We bowled well and hit the right lengths with the new ball and it was swinging nicely. We challenged the Indian batsmen with right lengths and took our catches to put ourselves in a really good position."
"It happened very quickly for us and they were all decent balls. It's not like the Indian batsmen will be kicking themselves for playing those shots. They certainly had to play at those deliveries. I can't remember a Test match where we knocked out a top-order like that.
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"The bounce was very good and getting a leg before was very hard. So it was good bowling because we didn't get carried away with that bounce," said Broad.
"The zip in the pitch went away to some extent so we did really well in the first hour and it was really good for us," he added.