Dean, Knight help England to their first win of the tournament
The defending champions built their case through a strong outing in the field, holding catches and capitalising on run out opportunities, bundling India out for 134.
Meghna Singh and Jhulan Goswami looked to have cracked England's top order, dismissing Danni Wyatt and Tammy Beaumont respectively (both for one), though Sciver's 65-run partnership with Knight steadied the ship. Sciver's knock of 45 from 46 balls helped England in the cause to bolster their net run rate.
M15 Match Highlights: England v India
England would also lose Amy Jones for 10, with Harmanpreet Kaur taking a stunning catch off the bowling of Rajeshwari Gayakwad.
Meghna Singh would also deliver a double blow in the 30th over, dismissing Sophia Dunkley for 17 and Katherine Brunt for a duck.
But skipper Heather Knight, calm as ever, ensured there were no hiccups, remaining unbeaten on 53 as England won with 112 deliveries remaining.
M15 Innings Highlights: England v India
India never found a rhythm with the bat despite a late 37-run partnership from Richa Ghosh and Goswami, who both fell to soft dismissals late in the piece. Meghna then fell to Charlie Dean, who completed England's potentially tournament-turning bowling performance.
Dean also claimed Harmanpreet Kaur, Sneh Rana and Pooja Vastrakar to finish with figures of 4/23.
Spin was key for the English, with Sophie Ecclestone turning the screws by trapping the set Smriti Mandhana in front for 35.
Anya Shrubsole started the dream run for England, clean-bowling Yastika Bhatia through bat and pad to bring up 100 ODI wickets, before claiming the big scalp of captain Mithali Raj for just one.
Sophia Dunkley claimed a tricky catch to remove the No.3, and a direct-hit run out from Kate Cross dismissed Deepti Sharma, hinting that England's fielding malaise may be behind the side chasing their first victory at the tournament.