After being carted by the West Indies on Tuesday, the Dutch restricted Ireland to 210 for 8 despite a half century from opening batsman Eoin Morgan. The Netherlands looked on course for a win for most of the match but Ireland were saved by some tight late bowling in the middle and end overs.
Seven runs were needed off the last over bowled by Kevin O'Brien but the visitors managed five to end on 209 for 6.
Skipper Trent Johnston elected to bat after winning the toss but openers Morgan and Kenneth Carroll had crawled to 33 in the 12th over before Carroll was trapped leg-before by Billy Stelling for 12.
Morgan - released by county Middlesex to play in the series - made a patient 51 off 112 balls before was caught mis-timing a pull. Andre Botha made a brisk 27 but desperation got the better of Niall O'Brien, who was run out for 22, and Trent Johnston (2) soon followed, holing out on the boundary.
Kevin O'Brien hit two huge sixes before he was caught at long-on by Eric Szwarczynski for 22. Alex Cusack (1) and Thinus Fourie (4) departed cheaply and the Irish eventually managed to surpass 200 thanks to Dave Langford-Smith's unbeaten 31 which included three huge sixes. Mudassar Bukhari smashed Langford-Smith for a four and a six in the third over as the Dutch appeared to take a firm grip.
The opener was run out for 71 in the 33rd over to leave his side on 138 for 2 and seemingly on course for victory.
But when Alex Cusack caught and bowled Bas Zuiderent for 36 the scoring rate came to a halt.
Szwarczynski (15) was snapped up by Kevin O'Brien off his own bowling and Botha removed Peter Borren with the first ball of the 47th to boost Ireland's hopes.
Hendrik-Jan Mol was then brilliantly run out by Kenny Carroll and Botha and O'Brien's experience at the death saw the Irish snatch an unlikely victory.
Ireland 210 for 8 in 50 overs (Eion Morgan 51, Kevin O'Brien 34, Langford-smith 31, Nic Botha 27; Mudassar Bukhari 3 for 43, Stelling 1 for 21, Mol 1 for 16) beat Netherlands 209 for 6 in 50 overs (M Bukhari 71, Zuiderent 36, Borren 27; Nic Botha 1 for 21, Kevin O'Brien 1 for 19) by one run.