Sciver and Danni Wyatt both made half centuries, before Charlie Dean took four wickets as Lewis' side made light work of West Indies
Antigua: England 307-7, West Indies 165 - England win by 142 runs
Nat Sciver inspired England to victory on her return to international cricket as Jon Lewis watched his side win comfortably in his first match as head coach.
Sciver made 90 off 96 balls after the tourists were asked to bat first at the Sir Vivian Richards Stadium in her first appearance for England since the Commonwealth Games.
The allrounder took part in The Hundred afterwards but then stepped away from the game to focus on her mental health and wellbeing for the final stretch of the summer, meaning she missed the September series against India.
She has come back without the vice-captaincy but otherwise showed all of her trademark power, hitting nine fours to guide her team, who were stuttering at one stage at the halfway mark in their innings, to a final total of 307 for 7 – England's highest ODI score in the Caribbean.
Sciver was well supported by Danni Wyatt, whose 60-ball 68 was invaluable in taking the game away from a West Indies side without the injured Stafanie Taylor and the internationally retired Deandra Dottin. The hosts were further hindered by a hamstring injury picked up by captain Hayley Matthews, who was forced to retire hurt early in her innings but came back later.
Nat Sciver made 90 with the bat and ran out Rashada Williams (Image: CWI Media)
Matthews had earlier been West Indies' best bowler, albeit going wicketless through her 10 overs. Tammy Beaumont (33) opened the England innings alongside Alice Capsey (17), who was preferred to Emma Lamb, and both made starts.
But Capsey edged a cut behind and her day was curtailed by injury when she landed awkwardly while diving at fine leg and had to be helped off the field after a lengthy delay, before going to hospital for further assessment on her left shoulder.
Sophia Dunkley fell cheaply, brilliantly caught on the deep point boundary by Shakera Selman diving to her left. On a day when 10 chances went down between the two teams, it was a rare positive in the field.
Heather Knight's return to cricket after a hip problem cut short her summer brought 16 runs, before the England captain was caught behind, a wicket that brought together Sciver and Wyatt for a 103-run stand in 15.4 overs. Wyatt swung away three sixes along with four fours, continuing even after Sciver was caught in bizarre circumstances, somehow looping an attempted scoop over short third to short fine leg via the back of her bat.
Amy Jones, batting at No.7 for just the eighth time in ODIs, continued that momentum on a slow, low surface. She made 30 before picking out cover in the penultimate over of the innings as England passed 300 for a third time in the calendar year.
England have an injury concern over Alice Capsey (Images: CWI Media)
In response, Aaliyah Alleyne spooned a catch to mid-on in Kate Cross' second over, before Matthews' misfortune effectively meant West Indies were two wickets down early. And while Rashada Williams and Kycia Knight rebuilt in a stylish partnership worth 70 runs, they couldn't score quickly enough to worry England.
Both batters could have been removed in consecutive overs, but Sophie Ecclestone dropped two chances in quick succession off her own bowling. Those weren't costly, though, with Williams run out by Sciver attempting a sharp single and Shemaine Campbelle – on the occasion off her hundredth ODI – chipping Charlie Dean to midwicket without scoring. Knight – Kycia – fell to her namesake, Heather, for 39.
Matthews' return to the crease was cut short when she misjudged the length of a Lauren Bell delivery and was trapped in front as she looked to pull, before Chinelle Henry and Cherry-Ann Fraser were bowled by Cross and Dean, respectively.
Dean then had Sheneta Grimmond well caught by Wyatt at deep midwicket, but she was denied a five-wicket haul by Dunkley, who was handed a rare bowl and finished proceedings by having Selman hole out to mid-on.