Sam Drury
BBC Sport journalist
Third T20, St Lucia
West Indies 145-8 (20 overs): Powell 54 (41); Mahmood 3-17, Overton 3-20
England 149-7 (19.2 overs): Curran 41 (26), Livingstone 39 (28); Hosein 4-22
England won by three wickets; lead five-match series 3-0
Liam Livingstone was dropped three times before taking England to a series-clinching three-wicket win over West Indies in the third T20.
Having been set 146 to win in St Lucia, Jos Buttler's side slipped to 37-3 in the powerplay but Sam Curran batted fluently for his 41 from 26 balls to lead the recovery.
England were well placed when he departed but it was left to Livingstone - having been dropped twice by Nicholas Pooran on six and eight, then again by Shimron Hetmyer on 21 - to try and finish the job.
The big-hitting all-rounder took 16 from an Alzarri Joseph over to put the tourists on the brink and although he holed out with four needed, England got over the line with four balls to spare.
Victory gives them an unassailable 3-0 lead in the five-match series, with two matches left to be played.
Saqib Mahmood and Jamie Overton had earlier taken three wickets apiece as England restricted West Indies to 145-8.
Mahmood took three wickets in the powerplay as the hosts slumped to 37-5 and despite a half-century from captain Rovman Powell, they were ultimately unable to post a winning total.
England had nervy moments in the chase but did what was required of them and head into Saturday's fourth T20 - also in St Lucia - with the series victory secured.
Mahmood and Overton do the damage for England
After a start delayed by 45 minutes because of a wet outfield, England’s bowlers came out firing.
They were given a helping hand by a combination of a mix-up between the West Indies openers and brilliance in the field from Jacob Bethell to run out Shai Hope.
Mahmood removed Evin Lewis in the next over before setting up Roston Chase superbly to have him caught at first slip in the fourth.
Jofra Archer bowled Pooran in between and when Mahmood had Hetmyer caught in the deep, West Indies were reeling.
For Mahmood, who exploited friendly bowling conditions brilliantly, it is now a record-breaking eight wickets in the powerplay in this series - the most by any bowler in a bilateral T20 contest.
Powell led the recovery with a well-paced half-century as he and Romario Shepherd steered West Indies away from immediate danger - both showing the Daren Sammy Cricket Ground was too small for them when they connected cleanly.
The Windies skipper reached his seventh T20 international fifty from 36 balls but just when he and Shepherd would have hoped to accelerated, the latter fell lbw after he was deceived by a superbly disguised Overton slower ball.
Overton removed Gudakesh Motie in the same over and then came back to have Powell caught in the deep to start his next.
There looked like being an element of symmetry to the innings before a late flurry from Joseph and Akeal Hosein ensured the hosts batted their overs to post a respectable total.
Livingstone makes Windies pay for dropped catches
While the pitch was no minefield there was certainly enough to keep the bowlers interested, so having got England three down early, West Indies would have been confident of pressing home their advantage.
The impressive Hosein removed Phil Salt and Buttler, England’s standout batters in the first two games, while the returning Joseph had Bethell caught behind.
However, Will Jacks showed resolve and Curran looked in good touch from the outset, elegantly stroking his first ball for four.
That pair got England back on track but the key moments came soon after Jacks fell to Motie for 32.
Livingstone came in and promptly carted Joseph into the stands for six. But two balls later, he skied a hook shot, only for Pooran to shell the catch as he ran back from behind the stumps.
The next over saw Pooran gift Livingstone another chance when he edged behind off Motie with the ball bouncing out of the wicketkeeper's gloves.
Curran's innings came to an end when he picked out Hope at deep backward point to hand Terrance Hinds a first T20I wicket, and had Hetmyer held on to a tough low catch to dismiss Livingstone in the next over, England may have been in trouble.
Instead, Livingstone took the attack to Joseph, clubbing a six and two fours in the over, and 21 from 18 balls required was suddenly five from 12.
He fell trying to finish the game in style but Rehan Ahmed came in and slapped the ball over cover to finish the job for England in the last over.
England can celebrate the series win but West Indies will know that but for some sloppy fielding, they might be right back in it.
'I feel really free in this team' - reaction
Player of the match, England bowler Saqib Mahmood: "As a bowling unit we've always had the mindset of wanting to take early wickets. We know their batting line-up is stacked all the way down but we haven't backed down and we have taken powerplay wickets in every game so far.
"I feel really free in this team now. It feels like my spot and it feels like a really great chance to express myself out there."
England captain Jos Buttler: "A real collective effort to win the series which is really pleasing. I've been so impressed with how we've set the tone in the powerplays in all three games so far.
"We're in a really strong place as a team. We've got really good competition for places too, when you consider the players who aren't here."
West Indies captain Rovman Powell: "It's a bit disappointing, we keep losing wickets in the powerplay and in clusters. We need to be our natural selves.
"We know we are stroke players and come out aggressively but that little element of being smart was missing."