West Indies only played at 60 to 70 per cent of their capabilities as they survived a scare to beat Papua New Guinea in their T20 World Cup opener, admits captain Rovman Powell.

The Windies followed the United States' lead in making a winning start on home soil on Sunday, though they were pushed close in a five-wicket win over the team ranked 20th in the world.

The co-hosts collapsed from 61-1 to 97-5 and needed 37 runs from their final 19 balls to reach their target of 137, but Andre Russell and Roston Chase combined to get them over the line.

They take on Uganda in their second match next Sunday before rounding off their Group C campaign against New Zealand and Afghanistan.

Powell knows they have work to do despite their victory, saying in his post-match interview: "Papua New Guinea's plans were simple, and they played some really good cricket. It is important to get two points in this tournament.

"Roston bowled pretty well, and to come out under pressure, with the way he played, it was what we needed.

"We are 60 to 70 per cent there. We can be better in all three departments. Hopefully, we can correct that for the second game."

Chase was named Player of the Match after hitting an unbeaten 42 off 27 deliveries, and he insists Windies did not take Papua New Guinea lightly.

"They're not an A-List team but we don't want to take any team lightly in the World Cup. We came out with the mentality that we were playing Australia or India," he said.

"We started slowly but we had a chat at the halfway stage and the guys just wanted to rally and put our best foot forward."