A superb 72 not out from Ibrahim Zadran, backed up by the bowling of Azmatullah Omarzai, gave the hosts victory in the final match of Ireland's tour against Afghanistan.
"It is a great series win for us," said Afghanistan captain Rashid Khan, going on to praise the performance of his young side.
The Irish were unable to chase down a target of 156, with Omarzai's four wickets for just nine runs helping bowl the tourists out for 98 inside 18 overs.
Ireland won the first T20I of the mini-series last week but consecutive wins on Sunday and Monday ensured Afghanistan recovered to take the three-game series, after earlier winning the ODI series 2-0.
For the third consecutive time, Khan won the toss against Ireland and as he did in Monday's 10-run win, he elected to bat first.
Batting at three, 22-year-old Zadran anchored Afghanistan's innings with his career-best T20I score of 72, which boosted the hosts to a total Ireland could not match.
Opener Rahmanullah Gurbaz rounded off a T20I series he will hope to forget on a personal level, after scores of zero and three in the first two matches, when Harry Tector took a superb diving catch to dismiss him for six at the start of the third over.
Afghanistan were then ticking along nicely with Zadran and Sediqullah Atal at the crease, until Atal chipped a turning ball straight back to Gareth Delany.
In the very next over, Omarzai, on back-to-back golden ducks, was dropped by Delany on one but departed just two deliveries later, after lobbing Curtis Campher to Josh Little.
Mohammad Ishaq's arrival steadied the ship for Afghanistan as he mounted a crucial fourth-wicket stand of 54 with Zadran, until the number five mistimed a lob on 27 and Paul Stirling snaffled up the ball.
With just over five overs left, Zadran kept the scoreboard moving along for Afghanistan.
Ijaz Ahmadzai ably deputised him at the end with 10 runs from three balls, including a monster six in the last over, before he was run out trying to get his partner back on strike for the final delivery.
Ireland's run chase never really got underway, especially after Naveen-ul-Haq bowled both Andy Balbirnie and Lorcan Tucker with consecutive deliveries in the second over.
Some resistance came from Campher and Delany's 36-run sixth-wicket stand but the visitors were never really allowed to form any partnership of great merit by Afghanistan's pace attack.
Omarzai, 23, claimed the keys wickets of Tector and George Dockrell, before removing Mark Adair and Barry McCarthy as Afghanistan took apart the Irish batting line-up.
Naveen-ul-Haq then bowled Ben White with a slower ball, bringing a close to affairs and securing Afghanistan a tight series win ahead of this summer's T20 World Cup.
Despite defeat, Ireland will still view the tour as an historic success after they won their very first Test match on March 1.
