The 32-year-old is not new to the role having served as the temporary vice-captain in the multi-format series against India last year in Haynes' absence.
Australia's Alyssa Healy continued to lead the rankings chart followed by England's Natalie Scive as both the batters had a superb show at the Women's World Cup.
Healy was selected as the stand-out female player in April following her match-winning innings of 170 in the Women's Cricket World Cup final.
As Australia women won their seventh ODI World Cup, their journey to the top has not just been about what happens on the cricket field
Riding on Healy's breathtaking hundred, Australia bossed their way to a record-extending seventh Women's World Cup title with a crushing 71-run win over traditional rivals England.
After the Australian onslaught, Sciver tried to keep England in the chase, but they fell short by 71 runs.
Healy, who was dropped on 41, toyed with the English attack in her mesmerising 138-ball knock, which is the highest-ever individual score in a World Cup final in both men's and women's cricket.
Opener Alyssa Healy set up the chase and skipper Meg Lanning scored 97 to help Australia beat India by six wickets at Eden Park in Auckland
ICC Women's ODI Rankings: Mithali Raj drops to fourth, Australia skipper Meg Lanning rises to second
Lanning is now just one and 15 rating points away from the top spot that's currently occupied by her teammate Alyssa Healy.
Australian bowlers struck at regular intervals, save a fine 99-run partnership between skipper Bismah Maroof and all-rounder Aliya Riaz, to restrict Pakistan to 190.