Shakib Al Hasan has broken the stand of century openers by sending Karunaratne out of the field with Robiul completing a good catch to get a wicket against the run of play.
Sri Lanka scored 129 for 41.3 over in the second day of first Test match at Mirpur's Sher-e-Bangla stadium on Tuesday.
Kaushal Silva and Kumar Sangakkara are on the crease.
On the first day, Bangladesh ends batting with a score of 232 runs.
Sri Lanka won the toss and chose to field first.
Bangladesh collapsed after the exit of Skipper Mushfiqur Rahim in what was a poor display of batting throughout the opening innings in the first Test against Sri Lanka.
Only four batsmen could score double figures after the Tigers ended their first innings following the early dismissal of the top order.
Sri Lanka: Kaushal Silva, Dimuth Karunaratne, Kumar Sangakkara, Mahela Jayawardene, Kithuruwan Vithanage, Angelo Mathews, Dinesh Chandimal, Dilruwan Perera, Shaminda Eranga, Rangana Herath, Suranga Lakmal
Bangladesh: Tamim Iqbal, Shamsur Rahman, Marshall Ayub, Mominul Haque, Mushfiqur Rahim, Shakib Al Hasan, Nasir Hossain, Sohag Gazi, Robiul Islam, Rubel Hossain, Al Amin Hossain