Chasing a relatively modest 122 for victory, skipper William Porterfield smashed nine boundaries as he raced to 46 from just 30 balls. In conjunction with Niall O'Brien (18), the pair added 52 in just 6.1 overs to set Ireland well on course.
Karim Sadiq (2-17) brought a semblance of control to the wayward attack, and having dismissed Porterfield, followed it up with the wicket of Andre Botha (5). That set about a nervous period for the Irish, as they went from 91-2 to 98-5 in the space of 12 balls.
Gary Wilson (16*), and John Mooney (9*) however settled the dressing room as they added an unbroken 26 to achieve the win with 11 balls to spare.
If the current skipper was the star with the bat, then it was the former captain who set up the win with the ball. Trent Johnston took 4 for 22 in an inspired spell, continuing his superb form of 2009.
Andre Botha (3-14) wasn't far behing Johnston in the bowling stakes, while a special word of praise for 17 year old George Dockrell. The left arm spinner showed just why he is so highly rated in Irish cricket circles, taking 2-11 in a superb display of control and variety.
Raees Ahmadzai (33*), skipper Nowroz Mangal (27), and Shafiqullah Shafiq (23), all got starts for Afghanistan, but no-one was able to break the shackles of a disciplined and penetrative Irish attack, who had the happy knack of taking wickets at crucial intervals.
It's a case then of third time lucky for Ireland who had lost their two previous encounters to Afghanistan in the World Cup Qualifier and Intercontinental Cup.
Ireland 124/5 (18.1 overs), (W Porterfield 46, P Stirling 21, Karim Sadiq 2-17) beat Afghanistan 121/9 (20 overs) (Raees Ahmadzai 33*, Nowroz Mangal 27, Shafiqullah Shfaiq 23, T Johnston 4-22, A Botha 3-14, G Dockrell 2-11) by five wickets.