There's difference between being out of runs and out of form: Smith

MELBOURNE: Australian batting mainstay Steve Smith always knew that he was "out of runs" but never "out of form" as he got back-to-back Test hundreds against India within a week of each other after 18 months of lull.

Having scored his 33rd ton in Brisbane, Smith equalled Sunil Gavaskar's then world record of 34 hundreds on the second day of the fourth Test at the MCG on Friday.

Asked how did he chug along all these days when big runs were not coming that easily, Smith dived deep into his inner core.

"Sometimes you can be hitting the ball really nicely, which I think I said to all you guys when I wasn't scoring the runs. I actually felt like I was batting pretty well. And there's a difference, I think, between being out of form and out of runs. So, yeah, I thought I was hitting the ball nicely," Smith said at the day-end press conference here.

"I mean, you've got to have faith. You've got to have a bit of trust in what you're trying to do. I've played the game for long enough now to know that you can have your ups and downs. Having some faith and confidence," said the man, who is expected to get to 10,000 Test runs before the five-match series concludes.

"I think you need a lot of luck on these wickets to get big runs as well, the ones we're playing at the moment. And last week I had my fair share. I think I got an umpire's call and got beaten on numerous occasions as to on other days, I would nick it.

"So, yeah, you need a bit of luck. But you've just got to have faith that you're going to turn it around."

Australia's batting was a lot more aggressive on the second day after resuming on overnight 311 for six but Smith said that while batting with Pat Cummins, there was no "general plan" as such.

"There wasn't really a general plan. It was just go out there and play. Yeah, there wasn't a real plan. It was just go out and play and see what's going on. I thought Patty (Cummins) played really nicely. Really good, positive intent.

"We were able to get a nice partnership together and take a bit of the momentum of the game from that point, I suppose."