Being four down for less than 100 has been a recurrent theme for Bangladesh's batting line-up this year. In response to India's 404 in Chattogram, Bangladesh slumped further to 97 for 6 and ended the second day on 133 for 8. A rejigged top order had given Bangladesh some hope, but it evaporated quickly, leaving them facing a battle for survival for the rest of the game.

Shanto's golden duck exposed Bangladesh's batting line-up. Yasir Ali and Litton Das, who batted at No.3 and No.4 respectively for the first time, were immediately under pressure. Debutant Zakir Hasan (20 off 45 balls) lasted the longest among the top four as Bangladesh collapsed to 56 for 4 by the 18th over.

Shanto and Zakir edged Mohammed Siraj's outswingers, while Litton and Yasir played on. Kuldeep Yadav then took care of Shakib Al Hasan, Nurul Hasan and Mushfiqur Rahim. Mehidy Hasan Miraz, who was the player of the series in the preceding three-match ODI rubber, is unbeaten along with No. 10 Ebadot Hossain.

"Losing eight wickets is disappointing, but you know this is Test cricket; another three days to go. We need to hang in there and we need to fight hard," Herath said. "Test cricket is not easy, always testing your skill, testing your temperament, your patience and there always is a situation, so in that case, you need to fight hard and have to have that gritty attitude.

"We are getting some momentum at some stage, but somehow we are losing that momentum. I don't think it's about technique but more about getting those decision-making right in certain situations."

Do Bangladesh's batters have a psychological weakeness? "When it comes to cricket, you always have to be a tactical guy," Herath said. "You can be a bowler or a batsman but to be in the middle you have to have that temperament, it should always come from your heart and mind.

"There is nothing wrong with the ability or skill, but we need to be more gritty on that and fight hard in the middle. Once you spend some time in there, you get kind of an easy situation. So we need to stay and wait for that time and that's what I expect from our guys."

Herath also urged Bangladesh to build partnerships like how India had done on the second day. Despite losing Shreyas Iyer early, R Ashwin and Kuldeep Yadav put on a 92-run eighth-wicket stand to frustrate Bangladesh and help drag India up to 404.

"There partnerships were well executed. They were 50 for 3 [48 for 3] at one stage," Herath said. "There was one partnership with Rishabh [Pant] and [Cheteshwar] Pujara, then [Shreyas] Iyer with Pujara. You need to have that kind of partnership in Tests. If you look at Pujara's innings, he scored 90 but played a lot of balls with his gritty attitude so we need to have bigger partnerships."