Bangladesh set a reachable target of 266 for Afghanistan in the first ODI in Mirpur.
Decided to bat first, Bangladesh managed to make 265 losing all wickets in the 50 overs.
Opener Tamim Iqbal scored a superb 80 from 98 balls.
Tamim, dropped on 30, hit nine boundaries while Mahmudullah smashed five boundaries and both the sixes of the Bangladesh innings to score 62 runs.
A quick 48 from 40 balls by ace all-rounder Shakib Al Hasan helped Tigers accelerate their score.
Imrul Kayes also contributed to Bangladesh innings with his patient 37 runs.
Tamim brought up his 33rd ODI fifty in the 22nd over.
With this 80-run, the Bangladesh opener became the first batsman to cross 9000 runs in ODIs.
Tamim and Mahmudullah batted together for 17 overs, and their partnership yielded 79 runs.
To open Bangladesh innings, Soumya failed to score a single run before being caught out by Afghans’ bowler Dawlat Zadran.
Dawlat Zadran picked four wickets for 73 runs including crucial Soumya and Shakib while Mohammad Nabi and Rashid Khan took two wickets each.
Earlier, Tigers won the toss and elected to bat first against the visitors in the first one-day international match of a three-match ODI series that started at 2:30pm.
Tigers will play all three matches at the national cricket stadium, with the second game on 28 September and the finale on 1 October.
Both teams made several changes from their previous ODIs, with Afghanistan right-arm fast bowler Naveen-ul-Haq making his debut.
For Bangladesh, Taskin Ahmed returned for his first international match since his suspension for an illegal bowling action in March.
Bangladesh: 1 Tamim Iqbal, 2 Soumya Sarkar, 3 Imrul Kayes, 4 Mahmudullah, 5 Mushfiqur Rahim (wk), 6 Shakib Al Hasan, 7 Sabbir Rahman, 8 Mashrafe Mortaza (capt), 9 Taijul Islam, 10 Rubel Hossain, 11 Taskin Ahmed
Afghanistan: 1 Mohammad Shahzad (wk), 2 Shabir Noor, 3 Rahmat Shah, 4 Hashmatullah Shahidi, 5 Asghar Stanikzai (capt), 6 Mohammad Nabi, 7 Najibullah Zadran, 8 Rashid Khan, 9 Mirwais Ashraf, 10 Dawlat Zadran, 11 Naveen-ul-Haq