Sydney: India are down on their knees in the second Test against Australia but former skipper Sourav Ganguly says it is not "impossible" to save the match but for that to happen Indian batsmen need to bat out of their skins.

India have already conceded a mammoth 291-run lead and three days' play is still left in the match, where a victory will hand Australia an unassailable 2-0 lead.

Ganguly sought to remind India the superb win against the same opponents at Kolkata in 2001, where India came up triumphant against all odds.

"I don't believe in the word 'impossible' in sport after what India did to Australia at Eden Gardens in 2001. We followed on 274 runs behind but came back to win the match by 171 runs, thanks mainly to V.V.S Laxman and Rahul Dravid's efforts with the bat and Harbhajan Singh's bowling on the final day.

"But can such a remarkable feat be repeated? To get even close to something like that - or indeed simply save this match, the Indian batsmen will have to bat out of their skins when they get their chance," Ganguly said.

The former India skipper said what hurt India the most was an off-colour Zaheer Khan.

"The first session was so important for India. It was not only a match-changing, but potentially a series-deciding, session. India was below par, mostly because senior bowler Zaheer Khan looked a little off his rhythm in his first spell. He is so important to this Indian bowling unit, the team's fortunes change with his form and he was off his game."

Ganguly also questioned Mahendra Singh Dhoni's decision to introduce part-time spinner Virender Sehwag early into the attack.

"The introduction of Virender Sehwag at the 20th over with the second new ball was baffling to everybody. This was India's best chance to pick up wickets and get back into the game, especially as there was so much time left."