The loss marked Australia's third defeat in four T20Is, having previously enjoyed a 12-match winning streak before being shocked twice by England in this year's Ashes.

Matthews' knock came after Australia faced similar challenges in that series, with England's Nat Sciver-Brunt twice hitting a century in the ODIs.

Australia bowled too full and wide to Matthews on Monday night, with the West Indies' captain hitting 11 fours and three sixes between backward point and cover. The hosts also dropped Matthews twice, as the momentum of the match swung away from them.

"I wouldn't say it's a concern. They're really good players, right?" Australia's stand-in captain Healy said.  "It just comes down to execution. If you're only hitting the stumps like 20 percent tonight, you're asking for trouble knowing how small [this] ground is.

"We said all along that there's going to be periods where we could potentially lose games of cricket, and that's happening. It's a good opportunity for us to learn from what is going wrong and try and fix it for the next one."

Australia identified the need for a Plan B with the ball as a key issue after India star Harmanpreet Kaur knocked them out of the 2017 ODI World Cup.

Changes with the ball and a more attacking approach with the bat prompted a six-year era of dominance for Australia that had not been seriously challenged until this year's drawn Ashes.

Healy insisted 'Plan B', or the lack of one, was not the issue at North Sydney Oval.

"We've got all the plans that we could possibly have in our heads and we've got the skills to be able to do it out there," she said. "We're just not executing when we need to, which we need to fix.

"We were too wide. You look at the way [Matthews] swings the bat, she's batting on leg stump, basically trying to open up the offside.  "We probably gave her a little bit too much room in that department."

Australia must win on Thursday night in Brisbane to avoid their first series defeat to West Indies.