Barishal needed to score 19 runs in the last over of the game to seal the match, but they only managed 8 runs and endured their second defeat of the event.
Tamim Iqbal, the captain of Barishal, won the toss and sent Chattogram to bat first, who posted a challenging total of 151 runs for seven wickets in 20 overs.
Tamim was the highest runs getter for Barishal posting 32 off 32 balls with one four and two sixes. Afif Hossain, who posted 24 runs, was the only other batsman to have reached 20-run mark.
Two left-arm seamers of Chattogram— Mustafizur Rahman and Shoriul Islam— took three wickets each and helped Chattogram ensure a third consecutive win. Mosaddek Hossain and Soumya Sarkar took one wicket each.
Barishal ended up at 141 for eight in 20 overs.
Earlier, unlike their first two games, Chattogram batted first and failed to have a solid opening stand as Soumya fell for five. He went to pull off Abu Jayed but only managed a top-edge and caught by Towhid Hridoy.
After losing the first wicket at 22, Chattogram got 28 runs in the second wicket stand of Liton Das and captain Mohammad Mithun. Chattogram captain was looking good in the middle, but after getting settled scoring 17, he was hunted by Sumon Khan.
Liton Das, who hit an unbeaten 53 in the last game, managed 35 runs this time before being dismissed by Mehidy Hasan Miraz. He moved across the offside to produce a good shot, but the fielder, Kamrul Islam Rabbi, at the short fine leg took a good catch.
Shamsur Rahman, who batted for the first time in this event, posted 26 off 28 with two fours while Mosaddek Hossain scored 28 off 24 balls with one six. They were trying to keep the hope of posting a big total for Chattogram alive, but they failed to continue on a good run. Kamrul Islam removed Shamsur while Taskin Ahmed bagged Mosaddek.
Shykat Ali, who got inducted to the playing XI of Chattogram replacing injured Mominul Haque, hit an 11-ball 27 with three sixes and one four.
Eventually, Chattogram posted 151 for seven in 20 overs.
For Barishal, Abu Jayed bagged two wickets while Sumon Khan, Taskin, Kamrul and Mehidy took one wicket each.