Moeen Ali crashed England's second-fastest one-day international hundred as they accounted for the West Indies in Bristol.
Third ODI (Bristol)
England: 369-9 (50 overs. Ali 102, Root 84, Stokes 73; Cummins 3-82, Holder 2-81)
West Indies: 245 (39.1 overs. Gayle 94; Plunkett 5-52, Rashid 3-34)
Match report
Moeen Ali won the Bristol six-fest with England's second-fastest one-day international century as they prevailed by 124 runs to go 2-0 up in the Royal London Series against the West Indies.
England have been installed as 4/9 favourites by Sky Bet for the next ODI on Wednesday with the West Indies available at 100/30.
Moeen, whose 53-ball hundred put him behind only Jos Buttler in England's all-time list of fastest ODI centurions, went from 50 to 100 in an astonishing world-record 12 deliveries.
He completed the job with his eighth six in the space of just 14 balls out of 369 for nine - England's highest total against the West Indies. Moeen is 14/1 with Sky Bet to end the fourth ODI as England's top bat.
The tourists were in no mood to go too quietly, despite Liam Plunkett's maiden five-wicket haul, and took the match maximum count to 28 - Chris Gayle (94) with six, including three in succession off Moeen - in their 245 all out.
England put themselves one more win away from sealing the series, with two matches left to play.
Joe Root (84) made a more studied bid for the headlines, posting most runs across all formats in an English international summer as he and Ben Stokes (73) first hinted at a formidable total in their fourth-wicket stand of 132 after West Indies won the toss on a cloudy morning.
Moeen (102) and Chris Woakes took over in an increasingly brutal partnership of 117 from 76 balls as 50 runs were smashed in successive overs from Miguel Cummins (three for 82) and Jason Holder.
Root and Stokes both went in a rush of three wickets for 11 runs as Cummins briefly interrupted home progress.
Stokes holed out on the cover boundary off Rovman Powell having hit two of his three sixes in succession off Ashley Nurse.
England had earlier made a sedate start.
The previously in-form Jonny Bairstow mistimed an easy return catch back to Holder, but Root was soon under way with three consecutive leg-side boundaries off Jerome Taylor as he and Alex Hales transformed the early scoring rate.
Hales went lbw on DRS when Cummins slanted one into him in his first over, however, and Eoin Morgan's wretched run continued when Holder found movement off the pitch too to have him caught-behind first ball.
Root and Stokes ruled until, for the second time in the innings, two wickets fell in consecutive overs.
Buttler lost his off bail to an outstanding delivery from Cummins - and after the same bowler had Root lbw aiming to leg, England had to reassess.
Seventh-wicket pair Moeen and Woakes did so initially.
But then Moeen, dropped by Gayle at point on 87, switched gear dramatically as England piled up 123 runs in the last 10 overs.
Evin Lewis announced the Windies' intentions in the chase, hitting two sixes from David Willey's first four balls only to mis-pull the fifth to mid-on, and Shai Hope was caught-behind driving in Plunkett's second over.
Marlon Samuels was arguably unfortunate that DRS detected what was interpreted as the thinnest of edges behind off Plunkett (five for 52).
Gayle's third six, off Moeen, had taken him past his 50 by then - but when Adil Rashid came up with the direct hit from midwicket to run out the 'Universe Boss' a whisker short of the line chancing a quick single, West Indies were up against it.
So it proved, as Jason Mohammed and Holder narrowed the margin but nothing more as the asking rate and Rashid (three for 34) took their toll.
Match Reaction
Asked how his remarkable innings ranked among his personal favourites for England, Moeen Ali said: "I felt it was right up there.
"I just had a slog really, and everything just seemed to come off. I just tried to watch the ball, keep my shape and then really go for it. Obviously at the time, I'm just trying to play as many shots as I can. I really enjoyed it.
"You don't think about it, and you just try to hit every ball for six really ... when it's there just have a good go, and keep going. I thought we'd got ourselves in, and it was time to press the button and play a few shots - and it's not a massive hit for six (here).
"Rooty and Stokesy did a fantastic job first of all. We were in a bit of trouble, and then again we lost those three (quick) wickets. We've both got to rebuild a little bit ... (but) when we felt like we got to a situation around 42 overs, where we're in a decent position here to really go, we both had to try to play a few shots.
"In the end, he was trying to get (off strike), because I felt like I was in the zone and everything was coming off. But I felt they bowled a little bit in the slot for me."
West Indies captain Jason Holder was disappointed his team allowed England to get away from them.
"The par score on this ground was probably 320," Holder told Sky Sports.
"We got off to a pretty decent start and kept up with the run-rate but kept losing wickets at crucial stages. Chris (Gayle) was exceptional, but we needed bigger partnerships."