Kumar Sangakkara scored an unbeaten 170 to help Sri Lanka reach 385 for five wickets at the tea interval on the second day of the second Test against Bangladesh on Wednesday.
Resuming the day on 154-1 having bowled out Bangladesh for just 62, Sri Lanka added a further 231 runs during the first two sessions to extend their lead to 323.
Sangakkara began the day on 51 and progressed smoothly to a 13th Test century, reaching three figures just before lunch with a straight six before passing 150 for the eighth time in his career during the afternoon session.
The 29-year-old left-hander has faced 290 balls, hitting 18 fours and two sixes.
Sangakkara added 128 for the second wicket with Malinda Warnapura (82), who missed out on a maiden century after top-edging an attempted pull stroke in the first half hour of the morning.
Skipper Mahela Jayawardene (49) then provided solid supported during a 98-run third wicket stand that ended soon after lunch.
Bangladesh were left ruing the position of their slip cordon as Jayawardene edged his seventh ball directly between the wicket-keeper and a very wide first slip.
Jayawardene also survived a straightforward caught-and-bowled chance on 28 off left-arm spinner Mohammad Rafique.
Bangladesh's fortunes changed in the afternoon session when pace bowler Shahadat Hossain blasted out Jayawardene with the new ball, surprising the Sri Lanka captain with some extra bounce as he tried to pull.
Chamara Silva (33) added 92 with Sangakkara before being brilliantly caught one-handed at slip by Mashrafe Mortaza off the part-time spin of Mehrab Hossain Jr.
Hossain (2-21) brought further relief two balls later as Tillakaratne Dilshan was bowled for a duck having missed a wild slog.
Bangladesh trail the three-match series 1-0 after losing the first game by an innings and 234 runs last week.
