Harshitha Samarawickrama scored 105 runs, becoming the third Sri Lankan woman to hit an ODI century.
Vishmi Gunaratne was the second to achieve this in the first match, and Captain Chamari Athapaththu leads with nine centuries.
Harshitha is also the fourth Sri Lankan woman to score a century in any international format. Athapaththu has two T20 centuries, and Chamani Seneviratne scored a Test century against Pakistan in 1999.
With her 124-ball 105, Samarawickrama became the third member of Sri Lanka’s ODI centurions club, one match after Vishmi Gunaratne had ended Chamari Athapaththu’s long spell as its sole representative.
Having pulled off their record ODI chase to win the first ODI, Ireland put up another impressive batting display after being sent in.
Achini Kulasuriya removed both their openers in her new-ball spell, and when Dilhari took out Orla Prendergast, their centurion from Friday, they were 77 for 3. Hunter and Paul got them moving with a 57-run fourth-wicket stand, before Athapaththu struck to send Hunter back for a 71-ball 66.