Sri Lanka ended defending champion West Indies' slim hopes of advancing to the semifinals with an emphatic 20-run victory in their last T20 World Cup game on Thursday.

Young batters Charith Asalanka (68) and Pathum Nissanka (51) toyed with the seven-man West Indies attack in raising Sri Lanka's highest total of 189-3 in their final Group 1 game by slamming powerful half centuries.

In reply, West Indies, which won the toss and elected to field, lost their power hitters cheaply before getting restricted at 169-8.

Shimron Hetmyer narrowed the defeat with a fighting unbeaten 81 off 54 balls, but Sri Lanka always looked favorite to sign off from the tournament on a winning note.

"These youngsters have been working hard, so I'm really happy," said Sri Lanka captain Dasun Shanka. "They worked really hard for this. They have a long career ahead and a lot of good cricket to come."

The 42-year-old Chris Gayle could score only 1, Andre Russell made only 9 while the world's new No. 1 T20 bowler, legspinner Wanindu Hasaranga (2-19), clean bowled Dwayne Bravo (1) and captain Kieron Pollard for zero as West Indies lost wickets with regular intervals in a steep chase.

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"(Hasaranga) is a gem. He's a superstar in the making," Shanaka said. "There's a lot of cricket to be played, we have to protect him as well (but) as a captain, I back him in every situation."

Inexperienced Sri Lanka bowed out of the tournament with four points in Super 12s, defeating Bangladesh and West Indies while losing to England, South Africa and Australia.

Two-time champion West Indies, having a solitary win over Bangladesh, takes on Australia in their last group game on Saturday.

"We have spoken time and time again, especially from a batting perspective, what we need to do as individuals and we have not done well," Pollard said. "A couple of young guys are putting up their hands but the experienced guys, myself included, have not done well."

West Indies had a mathematical chance to go through to the last four, but Asalanka and Nissanka combined in a brilliant 91-run second-wicket stand.

The West Indies' most experienced bowler Bravo was smashed for 42 off his four overs. Bravo finally broke the stand when Nissanka holed out in the deep in the 16th over.

Ravi Rmpaul and Jason Holder also couldn't impress and finished with identical figure of 0-37.

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The Sri Lanka fielders showed plenty of athleticism on the field with Bhanuka Rajapaksa and Chamika Karunaratne holding onto stunning catches to dismiss Roston Chase and Holder, respectively.

Hetmyer, who hit eight fours and four sixes, narrowed the margin of defeat in the last three overs through some big hitting against fast bowler Karunaratne (2-43) and Dushmantha Chameera (1-41).

"We are not going to hide from the fact that it's been disappointing for us," Pollard said. "I'm sure all the guys are hurting in that dressing room. It's something we didn't see coming, but we have to face the reality."