I don't see this happening
It will be tough but at present SL only trail by 200 runs and have 8 wickets in hand. If they can bat today whole day will have a lead of 150 runs approx and 100 runs tomorrow somehow they can manage to put a total of 250 runs for India to chase in fourth inning . This will put back pressure in India because batting on last day will be difficult and winning will be more important for them so they may be lose the quick wickets too and give SL outside chance to win the match as well.
I don't see that happening, it will be a miracle of SL can give India 250 target from this position. And even if they do, I don't think they have the bowling to trouble this Indian batting line up.
Its a pity to see the mighty Lankans like this at home, I think it will be many years now before they will be able to bounce back to competitiveness with top teams post Sanga era.