With Amla gone, I believe India will be the favourites.
They just have to keep chipping away.
Yes Amla wicket would be big hope for India to win this test. But South Africa aim for historic blockathon to draw this match. They have quality batsmen to do so. So, I guess still there are chances for draw as well as for India winning.
I don't think only Amla is the best batsman for SA. Still they have Villiers and du Plessis as of now playing best test cricket. du Plessis scored just 2 runs from 60 balls and that is not so easy in test match. South Africa require another 388 runs with still 7 wickets remaining to win match but anyway they are not playing for winning but trying there best to draw this test match.