JOE Root’s second century of the World Cup helped England cruise to victory over the West Indies at the Hampshire Bowl

But the celebratory mood in Southampton was punctured by injury scares for captain Eoin Morgan (back) and opener Jason Roy (hamstring).

The injuries could open the door for Hampshire captain James Vince, a substitute fielder yesterday, to make his World Cup debut against Afghanistan at Old Trafford on Tuesday.

Asked about his own injury issue, Morgan said: “It’s sore. I’ve had back spasms before and usually it only takes a few days to settle down.

“It’s unclear at the moment, but we’ll know more in the next 24 hours.

“This is in a different area (from previous back spasms). You normally get a good indication the following day.

“If it settles down, the improvement is the following day and then it gets better.

On Roy’s situation, Morgan said: “He’ll go for a scan tomorrow and it will be 48 hours before we have a result.

“When any two players go down it is a bit of a worry. But it’s not panic stations or anything yet, we’ll just see how we go in the next 48 hours and go from there.”

Asked if he would be ready to face Afghanistan, he added: “I don’t know. Like everybody, we’ll have to see how it pulls up.

“We’ll see how risky it is going into that game, because there’s another game that follows quickly.”

Daily Echo: Joe RootJoe Root

A commanding eight-wicket win against dangerous opponents was important in firming up England's semi-final prospects, though seeing two of their best batsmen limp from the field was a bitter pill to swallow.

Roy hurt his left hamstring sprinting at cover and Morgan headed straight for the pavilion after a back spasm, with neither man taking their usual places in the batting order.

England will be desperate for positive news from the treatment room but the pair were not missed on the day, a modest chase of 213 proving a walk in the park for Root, who opened for the first time in his international one-day career and made 100 not out in 94 deliveries.

Root had already played an unlikely role with the ball, taking two wickets with his occasional off-spin, and the role reversals continued with a Chris Woakes cameo at number three.

Having never batted higher than seven in his previous 91 appearances, the all-rounder was handed an emergency elevation and chipped in with an assured 40.

The game was brilliantly set up by the bowlers, Barbados-born seamer Jofra Archer and Mark Wood delivering with pace and purpose as they shared combined figures of six for 48.

Archer's first appearance against the team he had represented at Under-19 level had been much debated, but he took the moment in his stride as the Windies slid from 144 for three to 212 all out.

All eyes were on the 24-year-old after England opted to bowl first but first blood went to Woakes, scattering Evin Lewis' stumps with a toe-crushing yorker in the third over.

Woakes thought he had a second - the prize scalp of Chris Gayle - but was left aghast as a tough chance popped out of Wood's hands at third man.

Giving Gayle a second chance can be among the costliest mistakes in one-day cricket, and a smooth six down the ground suggested the price tag might be a hefty one. Yet the burly Jamaican never quite made England pay, making 36 before pulling Liam Plunkett to deep midwicket.

Wood made his own amends, ending a tortured knock by Shai Hope, before Nicholas Pooran (63) and Shimron Hetmyer (39) showed some backbone. Their 89-run stand frustrated England rather than hurt them but it was as good as got as the innings fell off a cliff inside 15 overs.

In the absence of Moeen Ali, overloked for the second game in a row, it was Root's seldom-seen off-breaks which kick-started a collapse of seven wickets for 68. Having last taken an ODI wicket 18 months ago he took a pair of gentle caught-and-bowled chances, Hetmyer and Jason Holder succumbing.

The door was open and Buttler, deputising for the absent Morgan, called on Archer and Wood to kick it down.

An edge from Pooran and a plumb lbw put on Archer on a hat-trick but he had to wait before making Carlos Brathwaite his third victim of the day. Wood, who passed a morning fitness test on his left ankle, was equally impressive, hustling Andre Russell with a short ball and cleaning up Shannon Gabriel.

Root replaced Roy at the head of the innings and joined fellow Yorkshireman Bairstow in ramming home the advantage.

They took 62 off the first 10 overs, Bairstow taking care of business and usual and Root piercing the infield with a selection of sweetly hit drives. The West Indies attack was dangerous on paper but a crushing disappointment in the middle, lacking the intensity of their English counterparts and throwing in regular boundary balls.

Even their minor triumphs came at a price, Russell thudding Bairstow in the helmet but buckling his own knee in the process. The first breakthrough came with 95 on the board, Bairstow uppercutting Gabriel to third man, leading to the surprise emergence of Woakes at number three.

Any doubts about the wisdom of the promotion were swiftly dispelled, getting off the mark with a punch for four then pulling Gabriel to the ropes. A 104-run stand made the result safe, Woakes falling just before the line but Root safely reaching his 16th one-day ton and third on the World Cup stage.

With three wins from four outings, England nudged up to second in the table ahead of inviting games against Afghanistan and Sri Lanka.

West Indies innings

CH Gayle c Bairstow b Plunkett 36 
E Lewis b Woakes 2
SD Hope † lbw b Wood 11
N Pooran c †Buttler b Archer 63
SO Hetmyer c & b Root 39
JO Holder (c) c & b Root 9
AD Russell c Woakes b Wood 21
CR Brathwaite c †Buttler b Archer 14
SS Cottrell lbw b Archer 0
O Thomas not out 0
ST Gabriel b Wood 0
Extras 17 (lb 5, w 12)
TOTAL 212 all out (44.4 Overs, RR: 4.74)
Fall of wickets: 1-4 (E Lewis, 2.6 ov), 2-54 (CH Gayle, 12.6 ov), 3-55 (SD Hope, 13.2 ov), 4-144 (SO Hetmyer, 29.5 ov), 5-156 (JO Holder, 31.6 ov), 6-188 (AD Russell, 36.2 ov), 7-202 (N Pooran, 39.4 ov), 8-202 (SS Cottrell, 39.5 ov), 9-211 (CR Brathwaite, 43.4 ov), 10-212 (ST Gabriel, 44.4 ov)
BOWLING: CR Woakes 5-2-16-1, JC Archer    9-1-30-3, LE Plunkett 5-0-30-1, MA Wood 6.4-0-18-3, BA Stokes 4-0-25-0, AU Rashid 10-0-61-0, JE Root 5-0-27-2.

England innings (target: 213 runs from 50 overs)
JM Bairstow c Brathwaite b Gabriel 45
JE Root not out 100
CR Woakes c sub (FA Allen) b Gabriel 40
BA Stokes not out 10
Extras 18 (lb 2, nb 1, w 15)
TOTAL 213/2 (33.1 Overs, RR: 6.42)
Yet to bat: JJ Roy, EJG Morgan (c), JC Buttler †, LE Plunkett, JC Archer, AU Rashid, MA Wood
Fall of wickets: 1-95 (JM Bairstow, 14.4 ov), 2-199 (CR Woakes, 31.5 ov)
BOWLING: SS Cottrell 3-0-17-0, O Thomas 6-0-43-0, ST Gabriel 7-0-49-2, AD Russell 2-0-14-0, JO Holder 5.1-0-31-0, CR Brathwaite 5-0-35-0, CH Gayle 5-0-22-0