Dhaka:Shakib Al Hasan and Shahadat Hossain shared five quick wickets to spark Sri Lanka's collapse on the opening day of the first Test against Bangladesh on Friday.
Left-arm spinner Hasan grabbed 3-43 and seamer Hossain 2-47 as Sri Lanka slipped from a healthy 119-1 to 172-6 at stumps after electing to bat.
Thilan Samaraweera was unbeaten on 20 and Chaminda Vaas had yet to open his account when the day's play was called off due to bad light.
Sri Lanka were on course for a big total following a 95-run stand for the second wicket between opener Michael Vandort (44) and Kumar Sangakkara (43) before faltering against the spin-pace combination.
Hasan started the slide when he had Sangakkara caught by skipper Mohammad Ashraful at mid-wicket. The Sri Lankan hit seven fours, including two in the spinner's one over.
Vandort fell two overs later, top-edging a pull off Hossain to be caught by Hasan at mid-wicket. His 124-ball knock contained a six over long-on off Hasan.
Hasan then bowled skipper Mahela Jayawardene (three) and Tillakaratne Dilshan (14) to put Sri Lanka under pressure.
Hossain's second victim was wicket-keeper Prasanna Jayawardene (three), who was caught by Tamim Iqbal at fine-leg while attepting to pull.
Only 12 overs were possible in the morning session after a delayed start due to heavy fog.
The hosts denied Sri Lanka a solid start when paceman Mashrafe Mortaza trapped Malinda Warnapura (14) leg-before in the ninth over with a delivery that came in sharply.
The five-day match is scheduled to end on Wednesday with a rest day on Monday for Bangladesh's election. The second and final Test starts in Chittagong on January 3.
Sri Lanka will then play a triangular one-day series, also involving Zimbabwe, from January 10.