Mahela Jayawardene and Upul Tharanga cracked classy centuries as Sri Lanka inflicted a thumping nine-wicket defeat on Bangladesh in the triangular one-day series in Dhaka.

Kumar Sangakkara had invited Bangladesh to bat first and, although Imrul Kayes (42), Raqibul Hasan (43) and Shakib Al Hasan (47) made starts, the home side managed only 249 for nine.

Jayawardene (108) and Tharanga (118 not out) then made short work of the total, the two combining for 215 in an immaculate opening stand as Sri Lanka cantered to victory inside 43 overs.

The win assures Sri Lanka of a spot in next week's final.

Openers Tamim Iqbal and Kayes had given the home side a decent start, although they were nowhere near as frenetic as they were against India yesterday.

Thilan Thushara, who shared the new ball with Nuwan Kulasekara, took the brunt of that initial assault, Tamim smacking him for two fours and a six.

However, off-spinner Suraj Randiv, pressed into service as early as the eighth over, conjured the breakthrough when he trapped Tamim in front, the batsman attempting a sweep and missing.

Kayes and Mohammad Ashraful shared a brief partnership for the second wicket, but that association was ended when Ashraful was brilliantly run out.

The former captain attempted a second run off Perera and dived to reach the safety of the crease, but the bat, although over the line, was in the air when a direct throw from Thushara at third man broke the stumps.

Kayes then fell just short of the half-century mark and Bangladesh's run rate - just under six until then - slumped as captain Shakib and Raqibul slowly rebuilt.

Raqibul, dropped on seven by Jayawardene, went on to add 77 for the fourth wicket with his captain.

Both batsmen fell short of the half-century mark, Raqibul slapping a poor delivery from Perera to Randiv at point and Shakib pulling Thushara straight to Tharanga at deep square leg immediately after he had called for the batting powerplay.

Shakib's dismissal sparked a collapse as Bangladesh lost four more wickets in the powerplay for the addition of only 32 runs and only just saw out their full quota of overs.

Bangladesh's only chance lay in early wickets, but those hopes receded quickly as Jayawardene - who joined the team only this week after failing to make the original squad due to a hamstring injury - and Tharanga began the pursuit in resounding fashion.

Jayawardene launched his innings with three boundaries in five deliveries off Rubel Hossain's first over and thereafter continued to attack with fluency.

Tharanga had kept pace, the duo easily seeing off the powerplay and then consolidating nicely once the field was spread.

An early fall of dew had hampered Bangladesh considerably and the visitors were never required to force the pace.

Jayawardene reached his 12th ODI century with his 12th boundary but fell shortly afterwards, edging Naeem Islam to wicketkeeper Mushfiqur Rahim.

Tharanga, dropped on 97 by Mushfiqur, reached his eighth century and his first against Bangladesh in 115 deliveries, and finished the task in the company of Sangakkara (17 not out).