Tri-Series, Dambulla: Sri Lanka 241-6 bt West Indies 191 by 50 runs
Sangakkara reached his 20th ODI half-century off 88 balls
Sri Lanka eased to a 50-run win over West Indies in the tri-series despite some big hitting from Dwayne Smith.
Captain Marvan Atapattu (70) and Kumar Sangakkara (79) put on 138 for the second wicket as the hosts made 241-6.
Farveez Maharoof took 3-9 in 10 overs as the Windies collapsed to 39-5 in reply and a rout looked on the cards.
Smith restored some respectability with two big sixes in his 68 but Muttiah Muralitharan (2-45) bowled him as Sri Lanka claimed their second victory.
For the West Indies - missing 10 established players - it was another comprehensive loss following the defeat by India on Sunday.
Scoring proved difficult for the third successive game at the Rangiri Stadium and Sri Lanka suffered an early casualty after Atapattu won the toss.
After a square drive for four, Upul Tharanga - playing in place of the injured Sanath Jayasuriya - was lbw after missing with an attempted pull off a delivery from fellow debutant Deighton Butler which kept lower than he expected.
Atapattu and Sangakkara struggled to get the ball away in a cautious opening, although the captain thrashed two Butler deliveries through the off-side for boundaries in the ninth over.
Sangakkara played a lovely cover drive off Jermaine Lawson and an authoritative pull off Tino Best as he got into his stride.
They had started accelerating when Sangakkara perished to a poor shot, hitting Narsingh Deonarine straight to Shivnarine Chanderpaul at cover, before the same bowler had Dilhara stumped.
Atapattu then paid for attempting a second run on Butler's fumble at long-off, only to see the paceman to throw accurately to keeper Denesh Ramdin, who ran him out by some distance.
Mahela Jayawardene's innings was exciting - and short. After slogging Lawson over mid-wicket for six, he was cleaned up by Smith's yorker.
When a direct hit from Smith at point rant out Tillakaratne Dilshan cheaply, Sri Lanka were 205-6 and in danger of folding in a hurry.
But Russel Arnold and Upul Chandana batted sensibly to help set a decent total which was put into perspective when the Windies top order collapsed in spectacular fashion.
Maharoof clean bowled Ryan Ramdass, who was making his one-day international bow, and had Xavier Marshall caught behind to leave the tourists reeling.
Dilhara then removed Sylvester Joseph and took a diving return catch off Chanderpaul, before Maharoof bowled Ricardo Powell through the gate and to leave the Windies side staring humiliation in the face.
Smith had other ideas and launched a blistering counter-offensive, which included 18 off one over from Chandana, as he made his highest one-day international score.
At the other end the cameos were entertaining but too brief - bravado mixed with naivety - with only Deonarine (23) and Ramdin (29) threatening to provide Smith the support he needed.
Sri Lanka: Marvan Atapattu (capt), Upul Tharanga, Kumar Sangakkara, Mahela Jayawardene, Tillakaratne Dilshan, Upul Chandana, Russel Arnold, Lokuhettige Dilhara, Muttiah Muralitharan, Dilhara Fernando, Farveez Maharoof.
West Indies: Xavier Marshall, Ryan Ramdass, Sylvester Joseph, Shivnarine Chanderpaul (capt), Ricardo Powell, Narsingh Deonarine, Dwayne Smith, Denesh Ramdin, Tino Best, Deighton Butler, Jermaine Lawson.