Sri Lanka beat Afghanistan by 155 runs to secure 2-0 series win
Afghanistan, set a target of 309 to level the series, were shot out for 153 inside 34 overs as leg-spinner Wanindu Hasaranga starred with four wickets.
Afghanistan were well placed at 128 for one in pursuit of their target, but once Rahmat Shah (54) and Ibrahim Zadran (63) were dismissed there was little fight from the rest of the batters.
The pair had added 97 runs for the second wicket and Asitha Fernando, playing his first ODI in 15 months, provided the breakthrough by having Ibrahim caught behind.
Leg-spinner Hasaranga then produced two wickets in an over as he trapped Rahmat leg before wicket, while captain Hashmatullah Shahidi was bowled.
Hasaranga was backed up by seamers as Dilshan Madushanka claimed two wickets in an over and Asitha Fernando, who also ended with two wickets.
Afghanistan collapsed losing eight wickets for 10 runs, as Sri Lanka dominated under lights.
It was a back to the wall unbeaten 97 by Charith Asalanka that enabled Sri Lanka to a total of over 300 runs.
The Sri Lankan vice-captain was involved in two crucial partnerships, first adding 111 runs off 98 balls with Janith Liyanage (50) for the fifth wicket.
A 50 run partnership followed for the sixth wicket with Hasaranga off 32 balls.
Asalanka scored 62 runs in 35 balls in the last 10 overs and finished unbeaten on 97, a score he hit off 74 balls with nine fours and two sixes.
Sri Lanka got off to a poor start, losing the openers with 36 runs on the board.
Captain Kusal Mendis and Sadeera Samarawickrama scored half-centuries, while being involved in a 103 run stand for the third wicket.
Both batsmen fell for poor strokes.
Samarawickrama hit one straight to mid-wicket, while Mendis took on the deep mid-wicket fielder but failed to clear him.
Azmatullah Omarzai was the pick of the bowlers for Afghanistan finishing with three wickets.
Afghanistan were sloppy on the field dropping as many as five catches, a performance that cost them dearly.
The third and final ODI will be played on Wednesday at the same venue.
The hosts won the tour's sole Test by 10 wickets. The current series will be followed by three T20 matches, all in Dambulla.