Australia men's coach Andrew McDonald has gushed over fast bowler Scott Boland following another starring display for his country on day two of the final Border-Gavaskar Test in Sydney.

Speaking to reporters post-play and after witnessing Boland's (4/42) across spells at both ends at the SCG, McDonald also admitted the 35-year-old is a strong consideration for selection even with the "Big Three" of Mitchell Starc, Pat Cummins and the currently injured Josh Hazlewood all fit.

"We're not surprised by Scotty's performances. Every time he plays, he does the job well.

"His ability to just be relentless on a length move the ball both ways, it's proving difficult, in particular on this (SCG) surface.

"He's always a genuine consideration Scotty, and every time he pitches up in the Australian colous he delivers.

"We're lucky to have those four quicks in Josh Hazlewood, (Pat) Cummins and (Mitchell) Starc and Boland."

It was Boland who kickstarted Australia's bowling charge in India's second innings, making a mess of KL Rahul's stumps (14), beating Yashasvi Jaiswal's forward defence on 23, and catching the outside edge of Virat Kohli's bat (6) to boast opening spell figures of 3/27.

With series honours and a potential World Test Championship Final spot on the line, he returned to dismiss Nitish Kumar Reddy (4), mistiming a drive to Cummins at mid-off.

McDonald hailed Boland for delivering on promises and plans put in place, particularly against Kohli, where the fast bowler has dismissed the India batter five times for just 38 runs in 104 deliveries.

"It's one thing to have a plan, but then to be able to execute that, the way that we have to Virat, (to) put him under immense pressure.

"And look, he's tried some things, he's walked out of his crease, he's tried different tactics as well, but clearly that relentless nature of in particular Scotty Boland in that matchup's been incredibly difficult for him to come back, but he's never an easy wicket."

Despite the dominance of Boland and the Australian quicks on day two, McDonald is wary of India's threat on the other side, with a potential target under 200 a tricky prospect on a spicy SCG surface.

"Low scoring games like this, it just heightens the pressure within it, so a long way still to go, there's going to be plenty of cricket, so we'll see what happens.

"(The loss of quick wickets are) just a symptom of where Test cricket is at.

"I think the quality of bowling, upfront, I think both attacks are blessed with some generational talent that we're witnessing."

"So we're not surprised by the nature of the games where a new batter coming in is always vulnerable, and we've seen that across the journey.

"But if you can get a partnership going, then you've shown that you can score runs on these surfaces."

On the other side, the status of series-leading wicket-taker Jasprit Bumrah is unclear after leaving the SCG during the second session of the day, with further news in the afternoon revealing the quick had been hindered by back spasms.

McDonald suggested India may have to come up with new plans, but is also wary of the work of the rest of the attack who shone in Bumrah's absence to give the tourists a slender first-innings lead.

"I think that's more for a conversation with the Indian team who they put out there, who they bowl when they bowl them it is up to them and we'll respond to what they give us,

"First and foremost we've got four wickets to get, try to keep that total as low as possible.

"You could say that it would be slightly beneficial for us, he can bowl on any surface anywhere, he's a threat any time we knew that coming into the series and he's an incredibly talented bowler."

"If he wasn't to be there, then India would have to come up with a new plan."

"We're here to win a series. Would we get great satisfaction out of winning a series against India? There's no doubt about that.

"We've won the toss and bowled a little bit of late, so we've put ourselves in those positions (of chasing) more often.

"I think if you've been there and done it before, then yeah, you take confidence in that to be able to navigate through those scenarios, in particular the lower order which potentially may be called upon tomorrow."