Adil Rashid collected a first ODI five-wicket haul as England left Ireland in a spin with a seven-wicket hammering in the first of the two-match series.
Ireland were 40-0 and 81-2, but lost 8-45 in a sorry showing against a rampant Rashid (5-27), while part-time spinner Joe Root (2-9) also chipped in as the visitors were skittled for 126 in only 33 overs in Bristol.
And England needed just 20 overs to chalk up the win, with Alex Hales scoring 55 and Root an unbeaten 49 as they continue to build towards the ICC Champions Trophy.
Ed Joyce (23) and Paul Stirling (20) failed to build on starts, while Andy Balbirnie's 30 off 38 provided a measure of resistance before he nicked Jake Ball (1-16) behind to spark the collapse.
Rashid had Gary Wilson (1) and Kevin O'Brien (4) trapped lbw before resoundingly finding Stuart Thompson's (4) off-stump.
Root took care of George Dockrell (0) and Rashid snared Niall O'Brien (16) and Tim Murtagh (11) to bring an end to Ireland's misery.
Jason Roy was dismissed for a duck in the first over after Dockrell took a sharp catch on the dive at midwicket off Peter Chase (3-44), but Hales was in good nick and found the boundary 10-times in his entertaining 39-ball cameo.
Hales got a big top edge that William Porterfield snaffled at backward point and Eoin Morgan (10) gave Chase a third wicket with a pull to fine leg, but Root and Jonny Bairstow (10 not out) picked up the remaining runs to complete a comfortable day's work.