Ireland beat Holland by 88 runs to put themselves on the verge of qualification for the 2015 World Cup in Australia and New Zealand.
Niall O'Brien scored 70, putting on a stand of 125 for the third wicket with opener William Porterfield, who made 79, as Ireland made 236.
His brother Kevin O'Brien then returned figures of four for 13 as the hosts slumped to 148 all out in 36 overs in their World Cricket League one-day international in Amstelveen.
Ireland now have 19 points from 11 games, four ahead of Scotland with a game in hand. That match is also against Holland on Tuesday and victory would secure World Cup qualification and the World Cricket League title.
The Dutch had been well placed at 77 for two in just 16 overs, but Kevin O'Brien ripped the heart out of the hosts' middle order, claiming his best figures in ODI cricket.
Kevin O'Brien's haul included the wicket of Tom Cooper for eight and Holland's top-scorer Wesley Barresi for 55, ending their hopes of chasing down the Irish total.
Paul Stirling (two for 28) had dismissed Stephan Myburgh (22) and Michael Swart (one), paving the way for his team-mate to finish the job.
Earlier, Ireland got off to an inauspicious start, losing Stirling (one) and Ed Joyce (22), both to Edgar Schiferli,
But Porterfield, who recovered from being dropped on nought, and Niall O'Brien got the Irish motoring before the latter was run out, his 70 coming from 107 deliveries and featuring four boundaries.
Kevin O'Brien struck a quickfire 32 from just 22 balls, with three fours and a six, but no one else was able to give Porterfield any noteworthy support.
He was the the ninth man out when stumped, his 79 coming from 118 balls and containing eight boundaries, but the Irish total proved more than enough.