Ace spinner Ravichandran Ashwin remains an injury doubt for the third Test against Australia, India coach Ravi Shastri said Sunday as he demanded his opening batsmen step up to ease pressure on Virat Kohli.

Ashwin was sidelined with an abdominal strain for the second Test in Perth and was sorely missed as Australia, led by off-spinner Nathan Lyon, won by 146 runs to level the series 1-1.

Shastri revealed Ashwin is racing the clock to be ready for the crunch Boxing Day Test in Melbourne, where the stakes are high in the four-Test series.

"As far as Ashwin is concerned, we are going to take a look and evaluate over the next 48 hours," Shastri said.

Left-arm off-spinning all-rounder Ravindra Jadeja is also carrying a niggle, but experienced batsman Rohit Sharma, who also missed Perth after hurting his lower back, is fit again.

"He has made a very good improvement but then again we have got to see how he pulls up tomorrow. But he looks good as of today," said Shastri.

India go into the Melbourne showdown with Kohli and number three Cheteshwar Pujara is fine form, effectively carrying their team during the Adelaide and Perth games.

But the opening pair of KL Rahul and Murali Vijay have struggled for runs and Shastri said that needed to change.

"It's a big concern," he said when asked about the failure of the openers to get a big score. "It's obvious and that responsibility and accountability has to be taken by the top order. They've got the experience, they've got the exposure over these last few years to get out there and deliver. It's about how strong you are in the mind."

There is no guarantee that Rahul and Vijay will retain their places with in-form Mayank Agarwal called up to the squad as a replacement for injured young opener Prithvi Shaw, who has been ruled out of the series.

Superstar captain Kohli scored a battling century in Perth but he came under criticism for his sledging and heated exchanges with Australian counterpart Tim Paine.

His animated wicket celebrations were also frowned upon, but Shastri said he didn't have a problem with his skipper.

"What's wrong with his behaviour? As far as we are concerned, he is an absolute gentleman," he said.

Shastri also denied India's morale had taken a hit by losing in Perth after their tense victory in Adelaide — their first Test win on Australian soil in a decade.

"Absolutely not. 1-1 in a series in Australia and we know we had our chances in Perth as well. They're ready," he said. "It's not often that we've been in a position where we've won one (on an overseas tour). It's 1-1. The boys know what they can do, what they're capable of and the potential that lies ahead."