I feel Barishal lost it from the 14/15th over. It was always going to be a tough chase but they (well basically Gayle) were doing well and in contention but after Gayle got his Century they should have upped the pace from the other (non-Gayle) batsmen.
Dhaka were bowling well and the spinners were not bowling so Gayle wasn't able to get the
s as before. When there aren't many balls left it is too expensive to try and take singles to get Gayle on strike. Both batsmen should have been looking to hit boundaries or atleast turn the singles into twos. They had plenty of wickets in hand so cameos such as Kabir Ali's 15 of 9 balls would have done the job. Alauddin Babu, Shuvo and particularly the icon player Nafees should all be capable of doing this.
Instead they opted to choose the plan of Mithun eating balls to get Gayle on strike and put all the pressure on Gayle to hit
s, even when it was evident that he wasn't able to as fluently as before.
Forgot to mention it was excellent bowling and captaincy from Mashrafe.