Kumar Sangakkara struck his fifth Test double century as Sri Lanka closed in on victory after two days of the second Test with Bangladesh in Colombo.
Sangakkara, who resumed on 51, reached his 13th Test century with a six.
He advanced down the wicket to chip the single he needed to reach 200, which included 20 fours and two sixes, at which point Sri Lanka declared 451-6.
The Tigers began well but lost four wickets for 11 runs in less than three overs to trail by 320 runs at 69-4.
Malinda Warnapura was out for 82 while debutant left-arm spinner Mehrab Hossain took two wickets in three balls after lunch.
Warnapura had added only three runs to his overnight score in 40 minutes when he miscued a hook to mid-wicket.
Bangladesh were left ruing the position of their slip cordon as Sri Lanka skipper Mahela Jayawardene edged his seventh ball between the wicket-keeper and a very wide first slip.
Jayawardene also survived a straightforward caught-and-bowled chance on 28 off left-arm spinner Rafique before falling to Shahadat for 49.
Mehrab slowed Sri Lanka's progress by removing Chamara Silva for 33 and Tillakaratne Dilshan for a duck in the space of three deliveries.
He had Silva caught low in the slips by Mashrafe Mortaza before bowling Dilshan after deceiving the batsman in the air.
The Tigers, bowled out for a meagre 62 in their first innings, made a defiant start to their second innings, with openers Javed Omar and Shahriar Nafees both hitting Lasith Malinga for two fours.
Nafees fired three successive boundaries off Dilhara Fernando as 48 were scored in only six overs before the all too familiar collapse.
Nafees edged a widish one from Chaminda Vaas and Jayawardene dived across from second slip to pouch a Rajin Saleh edge in the next over.
Vaas struck again in his next over, cutting one back to trap Omar, whose 28 contained six fours, and five balls later Mehrab edged into his stumps off Fernando.
Bangladesh are behind 1-0 in the three-match series after losing the first game by an innings and 234 runs last week.
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