Chasing a par 125 for victory, Stars lost Elyse Villani and Mignon du Preez within a space of two balls before skipper Meg Lanning was out in the seventh over for 22.
Thereafter, it was all over to Sciver and young Annabel Sutherland (30 not out) who steadied the ship, build on the innings and saw their team home to extend their winning juggernaut.
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Earlier, sent into bat first, Perth didn’t have the best of the starts as they would have liked. On a slower pitch where the ball wasn’t coming easily to the bat, the Scorchers' openers Sophie Devine and Beth Mooney struggled to find the gaps hitting only a single boundary in the entire powerplay.
Instead, they kept on singles and twos in order to keep the scoreboard ticking as the Women in Orange reached 32/0 in the first six overs until the destruction arrived.
Stars skipper Meg Lanning threw the ball to young Alana King and the 25-year-old didn’t disappoint giving the breakthrough picking up the dangerous Sophie Devine with her first ball of the day.
The New Zealand skipper went for a sweep but missed the fuller delivery on the middle only to hit her back leg. King, who celebrated her birthday just three days ago, returned in her second and bingo. This time it’s Amy Jones, whose miscued shot was taken easily by Erin Osborne.
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She repeated the same in her third with Mooney (27) being the victim. At the end of 11th over Scorchers scorecard read 52 for 4 with King standing at 3-0-7-3.
The backbone has been broken already. Nicole Bolton top-scored with 32 down the order but she lacked company at the other end as the likes of Heather Graham (18) and Sarah Glenn (19) perished after getting the starts to finish at 125 for 8 in 20 overs.
King finished with 3/16 in her four overs while Sophie Day (1/17) and Natalie Sciver (1/27) were the other wicket-takers for Stars.
Brief scores: Perth Scorchers 125/8 in20 overs (Nicole Bolton 32; Alana King 3/16) lost to Melbourne Stars 127/3 16.2 overs (Natalie Sciver 47*, Annabel Sutherland 30*) by seven wickets.