At VRA in Amstelveen Irish spinners Paul Stirling and George Dockrell recorded career-best figures to overshadow a dream debut by Netherlands fast bowler Bernard Loots (3-16) and bowl their side to a stunning 39-run victory.
The Netherlands, chasing 178 for victory, lost its last six wickets for six runs to be bowled out for 138 in 38.5 overs in a match which had no bearing on the final standing.
Off-spinner Stirling, who had earlier opened the innings and scored a dogged 33 in Ireland's 177 in 48.2 overs, recorded figures of 6.5-0-11-4, while left-arm spinner Dockrell returned figures of 10-0-35-4 as the Dutch side's captain Peter Borren's rush of blood, bowled by Dockrell for 47 with the score of 132-4, turned out to be the turning point in the match.
Stirling, for his all-round performance, was declared man of the match.
Earlier, Ireland's decision to bat first appeared to backfire as it plunged to 57-5 before a rearguard action led by John Mooney's maiden ODI half-century (54 off 71 balls with four fours and a six) lifted it 177 in 48.2 overs.
Saturday's final between Ireland and Scotland will be the ninth time the two traditional rivals will meet at the ODI level. Ireland enjoys a 6-2 head-to-head advantage, including a five-wicket victory in this tournament earlier this week at VCC in Voorburg.