George Dockrell struck the match-clinching boundary off the penultimate ball as Ireland, chasing 169, finished on 171-3.
The result was Ireland’s first win in any form of international cricket this season, with the side also having suffered three one-day defeats.
Congratulations to @cricketireland for winning the first T20I match by 7 wickets. We try again on Thursday!… https://t.co/L9NGapwQkY
— Afghanistan Cricket Board (@ACBofficials) 1660068304000
Ireland openers Paul Stirling (31 off 29 balls) and captain Andrew Balbirnie (51 off 38) got the hosts’ chase off to a good start with a stand of 61 in 7.3 overs at Stormont.
Wicketkeeper Lorcan Tucker maintained the momentum with 50 off 32 balls before Harry Tector (25 not out) and Dockrell (10 not out) gave Ireland a much-needed success.
Earlier, spinner Dockrell took 2-7 and paceman Barry McCarthy 3-34, with opener Usman Ghani top-scoring with 59, including six fours and two sixes for Afghanistan.
Player of the Match: Andrew Balbirnie 👏👏👏 https://t.co/S65Rt98ds9
— Cricket Ireland (@cricketireland) 1660071269000
The tourists’ total of 168-7 was bolstered by 30 runs off the final two overs, with Ibrahim Zadran hitting an unbeaten 29 off 18 balls.
The teams will return to Stormont on Thursday for the second of a five-match series.