West Indies won the toss and chose to field in the dead rubber game.
The Caribbean team posted 123/7 in their 20 overs with Najibullah Zadran being the top scorer with an unbeaten 48 runs from 40 balls with the help of four boundaries and a six.
Mohammad Shahzad contributed 24 runs from 22 balls with two boundaries and a six while skipper Asghar Stanikzai made 16 runs from 22 balls with six to his name.
Samuel Badree grabbed three wickets while Andre Russell took two wickets. Sulieman Benn and Darren Sammy dismissed one Afghan batsman each.
West Indies, chasing 124 runs to win from 20 overs, scored 117/8 in the run chase.
Dwayne Bravo made 28 runs from 29 balls after striking a four and six each. Johnson Charles contributed 22 runs from 15 balls after hitting a boundary and two sixes.
Mohammad Nabi and Rashid Khan grabbed two wickets each while Amir Hamza, Hamid Hassan and Gulbadin Naib took one wicket as well.