It's debatable. It wasn't like Indian bowlers have bowled 100 overs or above to be tired. They just bowled 60 odd overs between 5 bowlers. There were only 24 overs left in the day when Australia was bowled out. That is, another 6 overs between them that too in short bursts probably. They could have easily done it, may be could have even took another 2 wickets, and could have come back fresh in the morning and cleaned up the rest. Moreover, Aussie batsman morale was down. They were bowled out very quickly after their bowlers bowled 160 odd overs in the first innings. That would have played on their mind as well. And even if they could have got 350(Which looked highly unlikely), chasing 60 runs in 4th innings isn't a problem at all. Overall, IMO India should have enforced follow-on. But I think Virat and team management knew what they were doing and hopefully tomorrow India will win, even if there's some rain. Let's hope for the best.