Third T20, Chelmsford
England 144-5 (20 overs): Knight 66* (47); Matthews 3-32
West Indies 127-8 (20 overs): Matthews 71 (54); Bell 2-11
England won by 17 runs; win series 3-0
England withstood all-rounder Hayley Matthews' brilliance to win the third and final T20 by 17 runs and complete a dominant series clean sweep in Charlotte Edwards and Nat Sciver-Brunt's first series in charge.
Matthews was playing a lone hand in West Indies' pursuit of 145 for a consolation win at Chelmsford, but a rain delay with 48 runs required from the last 26 balls disrupted the chase.
They slipped from 109-3 to 127-8, with Lauren Bell claiming the game-changing wicket of Matthews for a sublime 71 from 54 balls in the 18th over.
Bell finished an exceptional spell with figures of 2-11 while fellow quick Em Arlott and left-arm spinner Linsey Smith also took two wickets each.
Matthews claimed 3-32 in England's 144-5, leading West Indies' much-improved bowling performance, but former captain Heather Knight's unbeaten 66 from 47 balls ensured England just had enough runs on the board.
After Danni Wyatt-Hodge was bowled from the first ball of the innings by Zaida James' spin for the second match in a row and Sophia Dunkley was caught behind off Matthews for three, Knight and new captain Sciver-Brunt rebuilt the innings from a stuttering powerplay of 24-2.
The experienced pair added 48 for the third wicket before Sciver-Brunt fell for 37, and Knight added a further 42 with wicketkeeper Amy Jones, who made a quickfire 22.
A three-match one-day international series begins in Derby on Friday, but England will be waiting on Knight's fitness after she could not take the field in the second innings because of a hamstring problem suffered during her knock.
There was plenty of discussion and hope that losing the England captaincy would allow Knight more freedom as a batter, and in her first two knocks since, that has already come to fruition.
She made 43 not out in the first T20 at Canterbury, and was not required to bat in the second, before finishing strongly by reaching her first international T20 half-century on home soil from 38 balls.
West Indies were rewarded for a much more consistent bowling effort, sticking to a simple plan of keeping the stumps in play and squeezing England's batters as much as possible with a little help from a surface which aided their spin-heavy attack.
It meant that Knight had to work through the gears, focusing on rotating the strike and picking the gaps in her partnership with Sciver-Brunt which came after England posted their second-lowest T20 powerplay score when batting first at home, with only two boundaries struck in the opening six overs.
After Sciver-Brunt was caught on the boundary at the end of the 11th over, Jones' counter-attacking knock took the pressure off during the the middle overs which allowed Knight to display more versatility, striking one enormous six over mid-wicket and producing an array of cheeky ramps and paddles off the spinners.
Her injury will be a concern as she struggled to run between the wickets in the final couple of overs, but it has been a highly promising return to the batting ranks.
There are questions surrounding Wyatt-Hodge's form, however, with 17 runs in three innings having already been dropped from the ODI squad for this series. The opener's 22 ducks are the most in men's and women's T20 internationals, and 11 of them have come first ball.