Heat lost their composure in the run chase against Scorchers spinners Lilly Mills and Alana King
Perth Scorchers 7 for 137 (Mooney 40, Jonassen 3-16) tied with Brisbane Heat 9 for 137 (Harris 41, Mills 3-28)
Super Over Perth Scorchers 0 for 14 beat Brisbane Heat 2 for 12
King, who moved from Melbourne Stars, took a brilliant caught and bowled to remove the dangerous Laura Kimmince while Mills responded strongly after the first ball of the final over had gone for four.
Earlier in the chase, Kapp had claimed the vital wicket of Harris, lbw trying to pull a delivery that was too full, after she had dominated the early stages. The scrambled thinking of Heat was summed up in the final over when Nadine de Klerk wandered out of her crease having completed a single and was run out.
Scorchers had started well in their Powerplay before Jonassen, in her first game back from injury, claimed Devine first ball. Beth Mooney anchored the innings but the rest of the order could not get going as they lost 4 for 30 in six overs. India legpsinner Poonam Yadav claimed Mooney as her first WBBL wicket.