Chasing 224 to win, Ireland could only muster 114 before being dismissed as Afghanistan took a 2-1 lead in the five-match series.
Ireland lost wickets at regular intervals and never really managed to get going, with only four batsmen posting scores in double figures.
William Porterfield fell victim to Alam in the sixth over, with Andrew Balbirnie (0) and Paul Stirling (11) being dismissed shortly thereafter by Mujeeb Ur Rahman.
Simi Singh and Kevin O’Brien managed to briefly revive the innings before the former departed for 20, triggering a collapse in the process.
O’Brien managed to hang on despite losing partners regularly until his stumps were rattled by Alam, who then dismissed Tim Murtagh for a golden duck but could not complete his hat-trick and returned with figures of 4/25.
James Cameron and Boyd Rankin showed some resistance but could only add 18 runs for the final wicket before the latter was trapped plumb by Nabi.
Earlier after being put in to bat, Afghanistan were in a spot of bother at 81-6 before half-centuries from Asghar Afghan, Mohammad Nabi and Rashid Khan saw them get beyond the 200-run mark.
A good run from skipper Asghar and Nabi lifted Afghanistan to 223 all out after a batting collapse from the top order had Ireland on top.
Afghan made 54 off 70 deliveries while Nabi top-scored with 64 to counter a spirited effort from Ireland's bowling attack that had left Afghanistan reeling early in the innings.
Rashid Khan also contributed with a fluent knock of 52 as he put on 86 runs with Nabi to take the attack to the opposition before Afghanistan were bowled out in 49.1 overs.
James Cameron-Dow returned impressive figures of 3/32 including Nabi's prized scalp while fellow spinner Andy McBrine and paceman Boyd Rankin claimed two each.
Afghan put on a crucial seventh-wicket partnership of 50 with Nabi to trigger his team's fightback before Rashid’s heroics with the bat took them to a respectable total.
The final ODI will be played at the same venue on Sunday (March 10).
afghanistan vs irelandAftab Alamandrew balbirnieAsghar AfghanMohammad NabiMujeeb Ur RahmanPaul StirlingRashid KhanWilliam Porterfield
First Published: March 8, 2019, 7:31 PM IST