Afghanistan lost six wickets for 52 runs in the morning session as Sri Lanka closed in on victory in the one-off test in Colombo on Monday.
The tourists, who resumed on 199 for one, slumped to 251-7 for at the break, just 10 runs ahead, after Prabath Jayasuriya took four wickets with his left-arm spin.
Afghanistan had reached 214 for one when Kasun Rajitha provided the breakthrough with the second new ball, having Rahmat Shah caught behind for 54 to end a 108-run partnership for the second wicket.
The wicket prompted a collapse as Afghanistan lost five wickets for 13 runs, with four falling in the space of 26 deliveries.
Ibrahim Zadran had taken his overnight 101 to 114 when Jayasuriya bowled him through the gate with a peach of a delivery.
Asitha Fernando claimed a second wicket in the innings when he had Ikram Alikhil caught at second slip.
AFGHANISTAN: Hashmatullah Shahidi (captain), Ibrahim Zadran, Noor Ali Zadran, Rahmat Shah, Nasir Jamal, Ikram Alikhil (wicketkeeper), Qais Ahmad, Zia-ur-Rehman, Nijat Masood, Mohammad Saleem and Naveed Zadran.
SRI LANKA: Dhananjaya de Silva (captain), Kusal Mendis, Dimuth Karunaratne, Nishan Madushka, Angelo Mathews, Dinesh Chandimal, Sadeera Samarawickrama (wicketkeeper), Asitha Fernando, Vishwa Fernando, Prabath Jayasuriya and Chamika Gunasekara.