World champions England, who had already won the first two matches of the three-game ODI series, scored 328 before Ireland chased down the target with one ball to spare and seven wickets in hand.
Paul Stirling was named Player of the Match for his 142 from 128 balls, which included nine boundaries and six sixes, while Andrew Balbirnie combined well with him, posting 113 from 112 deliveries.
Stirling and Balbirnie’s match-winning second wicket partnership was worth 214 runs in just over 30 overs, stealing away control of the third ODI.
Ireland’s final score of 3-329 matched that which they posted in the 2011 World Cup in Bangalore against England when they produced arguably their biggest ever upset.
Kevin O’Brien was the hero on that day with a century for the Irish and it was him who scored the winning runs as he eliminated any final over nerves to finish the job.
Earlier, England lost early wickets to slump to 3-44, with Ireland’s Craig Young doing early damage, before captain Eoin Morgan (106) and Tom Banton (58) combined to arrest back the momentum with a 146-run fourth wicket stand.
England continued to lose wickets but lower order runs from David Willey (51) and Tom Curran (38no) gave them something to defend as they were bowled out in the final over.
Ireland’s run chase was professional in every sense, keeping their cool even when Stirling was run out by Curran at 2-264 in the 42nd over.
Balbirnie fell to Adil Rashid three overs later but O’Brien (21no from 15) and Harry Tector (29no from 26) were steady, helping Ireland claim some important points in the new ICC World Cup Super League, which results in qualification for the 2023 event in India.