Australian star batter Steve Smith on Sunday said the last three years have been the most challenging of his illustrious career, thanks to Kookaburra changing their ball in 2020 by adding extra lacquer on a reinforced seam.

Lacquer is a plastic layer that hardens the ball while a reinforced seam makes the red cherry firmer and allows it to move around more.

However, Smith battled all these and more on way to a 33rd century on the second day of the third Test against India here.

It was first Test hundred in last 18 months, a very long gap for a batter of his stature.

"Since 2021 when they changed the Kookaburra ball, batting has definitely got more difficult, particularly at the same time wickets got greener as well. So it's kind of like a perfect storm coming together," Smith said at the customary press conference at the end of second day's play.

He said the challenge lies in playing out the first 30-35 overs when the ball moves around a lot and with world-class bowlers such as Jasprit Bumrah operating, the job gets even more difficult for the batters.

"I think particularly the first 35 overs, I'd say, of an innings is very challenging at the moment with the significant seam movement. But then kind of, as I said before, I think the ball stays hard.

"So if you get through that period and, you know, you've got some guys like Travis and Marshy and Alex coming in, the ball still bounces off the bat a lot harder than it used to.

"So, the last three years have probably been the hardest that I've experienced in my career. Batting-wise, in terms of the amount of movement that's been generated.

"You can see that in the way the scores have come down as well. And, you know, bowling averages come down, batting averages come down.

"And usually in the first innings of a game, if you're putting, you think back probably five years ago, you're seeing consistent 400, 500s being scored in the first innings. If you put a three in front of it these days, you're usually in a pretty strong position.

The 35-year-old batting mainstay was fortunate to have not got out in the early part of his innings but Smith admitted one needs a bit of luck these days to score big hundreds.

"If you get a big score, you're going to need some luck to do it. And you're going to have to play really well. Test by Test. I've been doing it for so long. So if I want to change a few different things, it really doesn't take me long to do it.

"Sometimes I do it in the middle of an innings. That's a part about adapting to situations and scenarios that are put in front of you and having the confidence to do it." His latest century placed Smith in second position in the list for Australia, surpassing Steve Waugh's 32. Only Ricky Ponting is now in front of Smith with 41 hundreds.

Needless to say, he was relieved to have scored his first hundred since June 2023.

"It was just nice to get to three figures. It's been a little while. It's been tricky the first couple of games. Had a couple of nice balls and got strangled down the leg side in Adelaide.

"I feel like I've been batting well the last month or so. It was kind of just sticking to my processes, trusting that it'll turn around." Thanks to hundreds by Smith and the in-form Travis Head, Australia finished the day at a strong 405 for seven, and will look to capitalise on the third morning after the first day saw minimal action owing to rain.

Smith said he has been feeling good in the nets. He compliment the top-order batters for negotiating the new ball that's been moving around prodigiously.

"A lot of credit has to go to the top three. They faced 50-odd balls each, which is a pretty good effort on that wicket out there. They played really well yesterday and then started, okay today.

"If we can sort of get to 30-odd overs when Travis comes in, it makes a big difference to the team. The seam probably starts to settle down around 30, 40 overs and the ball stays quite hard.

"This new ball that they changed in 2021 or whatever it is. So, you see guys batting at 5, 6, 7 that are able to hit the ball hard and get good value for their shots. That's the kind of way we've been shaping up.

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