Centurions Dimuth Karunaratne and Kusal Mendis made Ireland's wayward bowlers toil on Sunday to put Sri Lanka in a commanding position on day one of the first Test in Galle.
At stumps in hot and humid conditions in the sides' first Test series, the hosts were 386 for four with Dinesh Chandimal unbeaten on 18 and night-watchman Prabath Jayasuriya 12 not out.
After winning the toss and opting to bat, captain Karunaratne completed his 15th Test hundred before making 179 while Mendis scored 140, his eighth ton in the five-day format.
Opener Nishan Madushka was caught behind for 29 off Curtis Campher to give the Irish an early breakthrough. But Karunaratne and Mendis added 281 runs for the second wicket, beating the previous record in Galle of 253 set by India's Shikhar Dhawan and Cheteshwar Pujara in 2017.