Chasing Ireland's relatively modest total of 108 for 5, Scotland looked well poised to cause an upset as Rachel Scholes (20) and Fiona Urquhart (7) kept pace with the required rate sharing an opening stand of 30.
However, they collapsed in dramatic fashion losing six wickets for just three runs to leave them reeling on 33 for 6.
Veteran leg-spinner Ciara Metcalfe (2-5) started the rot dismissing both openers in her first over.
Skipper Isobel Joyce (2-1) also picked up two wickets in her solitary over, while teenagers Robyn Lewis (2-7) and Lucy O'Reilly (2-21) also took a brace apiece.
Scotland player/coach Kari Anderson (14*) and Sam Haggo (10) both reached double figures as they opted for batting practice in the final stages, finishing on 81 for 8.
Their total was helped by the concession of 13 wides by the Irish - 8 of which came from the only over bowled by Cath Dalton.
The Middlesex player had enjoyed better fortunes with the bat in the Irish innings scoring a run a ball 20.
Isobel Joyce top scored with an unbeaten 33 from 30 balls (4 fours), while twin sister Cecelia hit 21, as Ireland recovered from the second ball dismissal of Clare Shillington (2).
Laura Delany (12) and Kim Garth (11) also reached double figures as the Irish batters spent time adjusting to the stifling heat and slow pitch.
Ireland are back in action on Thursday when they take on Thailand at the same venue before they start the tournament proper on Saturday against fellow European side The Netherlands.
T20 WORLD CUP QUALIFIER WARM-UP
At Thailand Cricket Ground (TCG), Bangkok
IRELAND WOMEN 108/5 (20 overs, I Joyce 33*, C Joyce 21, C Dalton 20, L Delany 12, K Garth 11)
SCOTLAND WOMEN 81/8 (20 overs, R Scholes 20, K Anderson 14*, S Haggo 10, I Joyce 2-1, C Metcalfe 2-5, R Lewis 2-7, L O'Reilly 2-21)
Ireland Women beat Scotland Women by 27 runs.