Brisbane let slip a match-winning situation as they lost a flurry of wickets in the final overs of their chase of Perth’s total of 7-137.
The Heat scrambled two runs off the final ball to tie the chase and send the game into the one-over decider.
Some clean hitting from South African debutant Anneke Bosch lifted the Heat to 2-12, but New Zealand star Sophie Devine took it upon herself to clinch the result, hitting two sixes off Heat skipper Jess Jonassen.
It was a bitter pill to swallow for Jonassen, who had been the pick of the Heat attack on the way to 3-16 from four overs in the Scorchers innings to make a solid return to cricket after being out for almost two months with a lower leg injury.
Brisbane had the run chase seemingly in hand after a bright start from Grace Harris (41 off 27 balls) before she undid much of her good work with a unwise shot selection against South African speedster Marizanne Kapp.
Despite staying on top of the run-rate with regular boundaries, the Heat also continued to lose wickets, and crucial momentum in their chase.
The final wicket pair of Hancock and Poonam Yadav managed to salvage two runs, through a fumble at the bowler’s end from former Heat player Lilly Mills (3-28), but it merely prolonged the result in the end.
It had all looked so promising half way through the Heat run chase.
A treble of sixes from four balls spread across two overs coming up to the half-way point of the innings by Harris and Jonassen had Brisbane pushing hard towards their target.
Jonassen smote one off leg-spinner Alana King before Harris clubbed two in a row off Queensland teammate Mills, who did have the last laugh when she snuck one through her Fire captain’s defence to bowl her for 18.
Aside from Harris, no other batter exceeded 18 runs, as the chances for match-determing partnerships came and went.
Earlier, the Heat won the flip and elected for first use of the pitch after seeing ball dominate bat in the earlier game between the Hurricanes and the Sixers.
After some powerful hitting from internationals Sophie Devine and Beth Mooney, the Heat steadily worked back into the game to have the Scorchers 2-70 at the 10 over mark.
Astute bowling changes saw the wickets start to fall, with Jonassen claiming her second and international spinner Poonam Yadav snaring the dangerous Mooney and Heather Graham.
Pace bowler Nic Hancock showed she had the need for speed with one delivery in her opening over hitting 123.6km/hr, but also managed to deliver excellent variety to have 1-16 after four overs.
The Heat kept the Scorchers largely in check, with their tail lifting Perth to 7-137 after their 20 overs.
Perth was untidy early, and Harris and Georgia Redmayne took full toll on the lack of pressure to scoot away to a strong PowerPlay return.
The two teams meet again on Tuesday afternoon at Blundstone Arena before Brisbane relocates to Launceston to play a string of games in northern Tasmania.