A Hossein Zamani wonder goal cancelled out an Ovays Azizi own goal as India drew Afghanistan 1-1.
Chhetri's two goals in 13 minutes flipped the narrative on its head and lifted Indian morale.
Chhetri's two second half goals helped India go third in the group with a win over Bangladesh.
A win vs Bangladesh would boost India's chances of a 3rd place finish in the qualifying group.
Bangladesh came to India unknown, unappreciated, underestimated. They return having changed all that.
Though India were below par against Bangladesh, the fans in Kolkata showed how much they can get behind their side even on a bad day.
Adil Khan's late goal saved India's blushes in a largely disappointing display against Bangladesh.
Adil Khan's late header spared the hosts' blushes in a 1-1 draw against Bangladesh in Kolkata
India will go in as firm favourites when they take on Bangladesh in Tuesday's AFC World Cup qualifying match in Kolkata.
The draw for the first of Asia's World Cup qualifiers was made on Wednesday, even though FIFA has yet to decide how many teams will play in 2022.
Mahfuza Akhter of Bangladesh has beaten Australian rival Moya Dodd for a seat on the FIFA Council reserved for an Asian woman.