Australia A 99 for 4 trail India A 107 (Doggett 6-15) by eight runs

Konstas, the 19-year-old who has been the most talked-about player this season, edged behind in the opening over against Mukesh Kumar as he looked to drive, and Bancroft, after four single-figure Sheffield Shield scores, was given caught down the leg side although replays showed it came off the thigh pad. Bancroft, who couldn't force his way back into the Test side last season despite prolific domestic form, threw his head back in frustration.

Harris reached double figures but was unconvincing. He survived a huge appeal for caught behind and was then dropped on 8 at third slip by Baba Indrajith against a ball that straightened from around the wicket from Kumar. After the let-off he managed a pleasing on-drive but gave his innings away when he flashed at Prasidh Krishna, who is part of India's Test squad, and was sharply taken at second slip. Prasidh could have had a third late in the day when Cooper Connolly was given a life in the cordon.

To add to the intrigue McSweeney, who bats three in the Sheffield Shield but is No. 4 here to accommodate the three openers above him, played as solidly as anyone all day, facing 110 balls for his 29, to give further credence to the talk that he may yet be the solution at the top of the order.

Speaking earlier in the day in Melbourne, Australia head coach Andrew McDonald admitted there was more uncertainty around selection than is ideal, but the final decision would not come down to a single innings.

"I think sometimes you're pushed into a space where you can't give certainty a long way out," he said. "There is a balance in that we prefer to be more settled coming for the summer, no doubt. If you have certainly that's fantastic, but there'll be moving parts in the summer as well that create discussions and decisions about who's going to play the next Test. Whilst we want to give clarity and certainty, sometimes that's not always able to happen.

"There's a lot of context and consideration around body of work for those senior players in Marcus Harris and Cameron Bancroft. Clearly Sam Konstas hasn't been able to have that body of work behind him because of the limited Shield cricket that he's played, and Nathan McSweeney is somewhere in the middle of that.

"You take Sam for example, he's had limited experience in Perth, and then obviously up to the Gabba, so there's incredible challenges for players who haven't played in those conditions before, but it's not to say that he can't do that either - he's a fast learner."

The tone for the bowler-dominated day was set in the second over when India A captain Ruturaj Gaikwad was brilliantly caught down the leg side first ball by Josh Philippe. Jordan Buckingham added a second in his first spell with a lovely delivery to find the edge of Abhimanyu Easwaran who is another in India's full Test group.

Sai Sudharsan made a promising start before edging behind against Doggett to begin what would be a memorable day for the South Australia quick who was only in the side as a second reserve having been called up to replace the injured Liam Hatcher, who in turn had replaced Mark Steketee.

Doggett hit the perfect full length on a surface offering the quicks encouragement and troubled all the batters. After offspinner Todd Murphy had removed Indrajith on the stroke of lunch - given caught at short leg when it was unclear if bat was involved - Doggett really got to work after the interval as he scythed through the middle order.

Ishan Kishan flashed an edge behind looking to counterattack and Devdutt Padikkal, who had provided the most resistance and was the day's top scorer with 36, edged an attempted drive to give Philippe his fifth catch. Doggett's fifth came when he trapped Manav Suthar with a yorker and a career-best sixth when he cleaned up Prasidh to leave India A 86 for 9. Navdeep Saini (23) managed to lift the total into three figures.

"Sometimes you've got to give it to the opposition as well," he said on Thursday, a day before the third Test in Mumbai. "I think Mitchell Santner was outstanding in the last game, but yes, we'll keep working hard. We'll keep getting better. That's about it. Guys are putting a lot of hard yards in the nets. Yes, ultimately it's the results that matter when you're playing international cricket, but I don't think so that our skill against spin has actually gone down."

"Test cricket is about playing sessions," Gambhir said. "I think if we can start to learn how to play sessions, and the kind of quality we have in our batting line-up, I think if we end up playing four to four-and-a-half sessions, we'll have a lot of runs on the board."

The inability to meet this fundamental demand has highlighted the challenge that modern-day batters face in the era of T20 cricket. "We need to defend better," Gambhir said. "I think that is something which is important. And especially on a turning track. Because if you've got confidence on your defence, a lot of things can be sorted. And that is something which we need to keep getting better, keep working on.

"Because, again, I'll keep going back to the same answer that a lot has to do with limited over-cricket and T20 cricket as well that when you're so used to muscling the ball, that you end up forgetting the soft hands and all that stuff, which probably used to happen eight or 10 years back. So that is something, that is why I said that a complete cricketer is a cricketer who plays T20 format really successfully and also the Test cricket really successfully. He can adapt his game. And that is what growth is.

"Growth is not only going about hitting the ball in the stands. It's also about batting sessions on a turning track, where you know that you will not be able to hit in the stands, but you will be able to rotate better. For that, I think the foundation is very, very important."

The Mumbai Test is likely to be played in conditions that should help the spinners as well. At the end of India's practice session on Thursday morning, the captain Rohit Sharma and Virat Kohli took a good, long look at the pitch with assistant coach Abhishek Nayar. Kohli then left, but Gambhir and bowling coach Morne Morkel joined Rohit and Nayar and the four of them were involved in a discussion that lasted about 20 minutes. A little while later, the groundstaff began to brush away whatever grass that had managed to cling to the surface. Batters may have to unlearn the skills that help them succeed in T20s to do well here. But is that possible? Can a coach help them make that switch?

"To a certain extent, yes," Gambhir said, "To a certain extent, it has to come from the individual as well. That how much value does he end up giving it in defending the ball? That is something which is very important. And especially on a turning track. Because I've always believed that the best players and the most successful players in this format, or be it any format, always had solid defense. So that is something which we keep talking about. And it is not the overnight thing that we're going to talk about it today and people will start getting better tomorrow. But it's a continuous process. We need to keep working on it. We need to keep telling people the importance of defense."

Could India end up facing a situation where they have to look at a separate set of players more suited to Test cricket? Gambhir couldn't commit to a hypothetical question but he did admit that "going forward, obviously, we will have to identify players who are solid red-ball cricketers. Because ultimately, to get the results, you will have to work really hard for three or four days or five days to be honest. So sometimes, as I just mentioned, it's important. If we can bat sessions, we know that we've got the bowling attack to take 20 wickets. At the moment, it's difficult to answer."