Opener Paul Stirling blazed 177 to claim the record one-day international score by an Ireland player.
It helped his team post 325 for eight in their match against Canada in Toronto.
Stirling, who turned 20 earlier this week, hit 21 fours and five sixes as he brought up his maiden ODI century and beat the previous Irish best of 142 score by Kevin O'Brien.
Ireland's total was also their highest in an ODI as they bettered the 308 for seven they managed against the same opposition in February 2007.
© Press Association