Bangladesh suffered a sudden blow in the Galle Test as Musfiqur Rahim and Litton Das fell in quick succession after Bangladesh passed the 450-run mark.
Mushfiqur made 163, while Litton fell for 90 after forming a 149-run stand.
These double blows made it tough for Bangladesh to go for a total more than 500.
Bangladesh were at 292 for three at the end of day one. Following an early setback of losing three wickets inside 17 overs, Mushfiqur and Shanto formed a solid stand of 264 runs.
Galle Test: Bangladesh pass 400-run as Mushfiqur crosses 150
During the partnership, both Mushfiqur and Shanto hit a century each.
It was the 12th century for Mushfiqur in his career, and the second in Galle after his double-ton in 2013.
Shanto fell prey to Asitha Fernando with only two runs short of 150. He was caught at mid-off. Angelo Mathews, who is playing his last Test, grabbed a low catch to send Shanto back.
Bangladesh, after winning the toss and opting to bat first, saw Litton and Mushfiqur forge a 100-run partnership, propelling the Tigers past the 400-run mark despite the absence of key player Mehidy Hasan Miraz due to illness.