Kamalini's batting was all about precise placing and finding angles rather than power as England bowlers ran out of options against the left-hander.
Australia put themselves squarely in the hunt for an ICC Under-19 women's T20 World Cup semi-final spot, after they outclassed India by seven wickets in their Super Six clash.
Shafali, who has already played 51 T20Is, 21 ODIs and two Test matches for the senior team at the international level, looked in excellent touch as she toyed with the South African bowlers and put her side on course for a big win.
Invited to bat, Shafali, a regular in the India senior team, and Sehrawat, stitched a 111-run stand for the first wicket.
Opener Shweta Sherawat smashed an unbeaten fifty after Parshavi Chopra's triple strike as India notched up a comprehensive eight-wicket win over New Zealand to storm into the final.
A stunning spell of leg spin bowling by Parshavi Chopra led India to an emphatic seven-wicket triumph over Sri Lanka in their second Super Six match in the inaugural ICC Under-19 Women's T20 World Cup.