Sri Lanka beat Ireland by 79 runs to win the first one-day international at the Clontarf ground in Dublin on Tuesday.
After losing the toss, Sri Lanka made 219 for eight in their full 50 overs before dismissing Ireland for just 140 in reply with more than 10 overs to spare.
The two-match series concludes at Clontarf on Thursday.
Sri Lanka 219-8, 50 overs
Ireland 140, 39.5 overs (S Lakmal 3-29)