Afghan Voice Agency(AVA)_Monitoring, Batting first after winning the toss, Afghanistan posted 294-8 as they played all the mandated 50 overs at Pallekele International Cricket Stadium.
Ibrahim Zadran scored 106 off 120 balls, including 11 fours. Rahmanullah Gurbaz followed with 53 while Rahmat Shah made 52. Najibullah Zadran contributed with 42 off 25 balls.
Chasing the 295-run target, Sri Lanka were all out after 38 overs.
Opener Pathum Nissanka was their highest scorer with 85. Wanindu Hasaranga de Sliva made 66.
Fazalhaq Farooqi was the pick of the bowlers for Afghanistan as he claimed four wickets. Gulbadin Naib followed with three wickets. Yamin Ahmadzai took two while Rashid Khan picked up one.
The sides will meet for their second ODI on Sunday.