Debutant Yasir Ali was looking sharp with his defence since the last session of yesterday and early in today's morning session.
However, the middle order Bangladesh batter's good-looking innings had to be cut short due to a head injury.
Shaheen Shah Afridi bowled a bouncer on the fifth ball of 30th over, which Yasir Ali failed to duck under clearly.
The ball hit the back of Yasir's helmet and he was taken back to the dressing room an over later as retired hurt after the physio assessed the situation closely.
Yasir Ali was batting on 36 off 72 deliveries with 6 boundaries before the ball struck the back of his helmet.
Bangladesh team management requested the match referee for a concussion sub of Yasir Ali, and they got the permission to field Nurul Hasan Sohan as his replacement to bat for the rest of the second innings.
Other than Nurul, Bangladesh could have asked the match referee to field uncapped Mahmudul Hasan Joy as he is as well a like-for-like substitute of Yasir Ali.
The concussion substitution rule began back in 2019 when Australia's Marnus Labuschagne replaced Steve Smith in the second innings of second test of Ashes following Smith's head injury.
Marnus played a brilliant innings and scored 59 off 100 deliveries.
Previously for Bangladesh, Liton Kumar Das and Naeem Hasan was substituted by Mehidy Hasan Miraz and Taijul Islam in the same test two years ago at Kolkata against India. which was also the first and only day-night test Bangladesh played so far.