Steve Smith, arguably Australia's finest batsman since Don Bradman, was left stunned and angry by his dismissal during the tourists' calamitous batting collapse in Delhi.

Australia's hopes of winning a Test series in India for the first time since 2004 went up in smoke during a diabolical 90-minute capitulation in their second innings.

Smith was bowled by star India spinner Ravichandran Ashwin attempting his first sweep shot of the series as Australia lost 8-28 when they were in a winning position.

The 33-year-old knows he needs to be calmer at the crease in the third Test, starting on Wednesday, with Australia heading to Indore down 0-2 in the four-match series.

Not only is he the best and most experienced batter in Australia's XI, Smith will fill in as captain this week after Pat Cummins opted to remain in Sydney to be with his seriously ill mother.

"I've played, what, (94) Test matches, and I don't think there's been too many times I've walked off the field and I've gone, 'What the hell am I doing?'," Smith said in Indore on Tuesday.

"I was pretty angry. There hasn't been too many times in my career where I've actually come off and just been bedazzled by what I've done. It wasn't my finest moment.

"We don't have to play at such a high tempo and risky tempo.

"Because we had them where we wanted them, we had men (available) and the ability to get off strike. We just rushed it."

Australia will make at least two changes for the third Test, with opener David Warner joining Cummins in leaving the tour after breaking his elbow in Delhi.

His absence will allow Travis Head to again open with Usman Khawaja after successfully filling in for the 36-year-old Warner during the second innings.

Star quick Mitchell Starc will likely fill the void left by Cummins, although he admits he will be hindered by his injured finger.

Australia have missed the speedy left-armer since he broke his finger while fielding during the Boxing Day Test against South Africa at the MCG.

The demolition of the Proteas in December proved to be a costly affair for Australia, who also lost allrounder Cameron Green to a similar injury.

But the pair will both play in Indore, with Green almost certain to replace Matt Renshaw in the top-six.

New spin sensation Todd Murphy suffered a slight side injury during the second Test but Australia still expect him to play alongside veteran Nathan Lyon and left-armer Matt Kuhnemann.

"It certainly helps with Greeny available, giving us two genuinely quick options (alongside Starc)," Smith said.

"It gives us the ability to play three (spinners) if we want to. The surface looks pretty similar to the last couple of Tests.

"I dare say we are going to see a lot of spin bowled in the Test ... it's certainly an option for us."

Ashwin and spin partner Ravi Jadeja have destroyed Australia in the first two Tests, weaving their magic on turning pitches.

"He's (Jadeja) done what he's done for a long time now, there's (not) too much difference," Smith said.

"When you are starting against that (spin) it's extremely hard but you still have to be really switched on every ball ... to ensure you aren't getting out the ways he's trying to get you out."