Sri Lankan skipper Ashan Priyanjana top scored with 111, and received excellent support from Chathuranga de Silva, Mahela Udawatte, and Danushka Gunatilleke.
The trio all scored half centuries as their side compiled an imposing 329 for 8 in their 50 overs, benefitting from an excellent pitch and a lightning fast outfield, which offered full value for their strokes.
The Sri Lanka top order punished anything remotely loose, striking a total of 49 boundaries, which the Irish attack found difficult to stem.
Andrew White showed all his experience to take 1-29 in his 10 overs, while Craig Young bowled excellently to finish with 4 for 44.
The Irish reply got off to to the worst possible start as Wednesday's centurion Stuart Poynter gave a return catch to leg-spinner Seekkuge Prasanna (5-50) from the first ball.
Andrew Balbirnie (2), Nick Larkin (16) and Andrew Poynter (1) fell cheaply as Ireland stumbled to 47 for 4.
John Anderson struck five boundaries in his 32 before being bowled by the impressive Chameera (3-34).
Stuart Thompson went on the offensive, striking 3 sixes and 2 fours in his 51 from 52 balls, sharing a 6th wicket stand of 66 with Andrew White (45).
Andrew McBrine (31) and Eddie Richardson (27) continued the late order rally, adding 50 in just 33 balls for the 8th wicket, but the dismissal of McBrine saw three wickets fall for just a single as they finished on 222 all out.
The teams meet again on Sunday in the third game of the series at Coleraine (10:45am).
At Stormont,
SRI LANKA A 329-8 (A Priyanjana 111, C de Silva 61, M Udawatte 60 D Gunathilaka 55, C Young 4-44) beat IRELAND 222 all out (41.3 overs; S Thompson 51, A White 45, A McBrine 31, E Richardson 27Prasanna 5-50, Chameera 3-34) by 107 runs