It was an anti-climax after the game was shaping up to be an intense contest. Kusal Mendis' maiden ODI hundred took Sri Lanka to a formidable 311, but Taskin Ahmed's hat-trick in the last over capped off a fine last 10 overs for Bangladesh.
Taskin first had Asela Gunaratne caught at mid-off off the third ball of the final over. Suranga Lakmal was the next to go when he holed out to midwicket. Nuwan Pradeep, having the unenviable task of keeping out the hat-trick, was bowled off an inswinging yorker.
That meant Taskin was the fifth Bangladeshi after Shahadat Hossain, Abdur Razzak, Rubel Hossain and Taijul Islam to reach this milestone, which he celebrated with his typical spread-eagle celebration.
A win for Bangladesh would have given them their first bilateral ODI series win over Sri Lanka, but that was always going to be tough given no side had ever chased down over 300 to win in Sri Lanka.
That Bangladesh got into the game was thanks largely to a lower-order collapse from the hosts - they lost their last six wickets for 40 to end up at least 20 short of what they looked set to get. Mendis built the platform through two vital stands: 111 for the second wicket with Upul Tharanga and 83 for the third wicket with Dinesh Chandimal before the collapse.
Tharanga, playing in his 200th ODI, steadied Sri Lanka after they lost Danushka Gunathilaka in the third over. He struck Mehedi Hasan, the offspinner, for two fours in the eighth over before leaning into a beautiful cover drive off Mustafizur Rahman in the 10th over.
Mendis was scratchy to begin with, a healthy edge flying between Mushfiqur Rahim and Mahmudullah at a wide slip position to reprieve him early on. Having scored just seven off his first 25 deliveries up until then, the boundary released the pressure. From there on, though, he was a different batsman.
The control with which he was batting resulted in Tharanga slipping into the role of an accumulator. The pair raised the century stand and looked good for more, but Bangladesh had a breakthrough in bizarre circumstances. Tharanga, trying to steal a run after Mushfiqur half-stopped a Mustafizur beamer, was run-out for 65 at the bowler's end through a direct hit from Mahmudullah at short fine leg in the 25th over.
Mendis hammered the next ball, a free-hit, for a six and then reached his fifty with a boundary off the fifth delivery. Mustafizur conceded 20 off the over, with Sri Lanka showing no signs of slowing down. He reached his century in the 36th over, thereby raising the possibility of hauling his side close to 330. But the dismissals of Chandimal and Mendis in successive overs set them back.
Mendis' dismissal - taken off the rebound by Taskin on his followthrough - left Sri Lanka at 216 for 4 in the 38th over. Milinda Siriwardana and Asela Gunaratne then patched things together with a 55-run stand for the fifth wicket.
Mehedi who dropped Siriwardana on 24 at midwicket had the last laugh when he bowled him in the next over. Gunaratne though continued to bring out his paddles and the big heaves to hit a 29-ball 39 to take Sri Lanka past 300 before Taskin took centrestage in the final over. However, rain had the final say.