The Hurricanes bowled the Scorchers out for 138 at the WACA Ground in Perth on Saturday night - after the home side lost their last seven wickets for 20 runs in 27 balls, amid a calamitous 8-33 collapse - before hauling in the target with 14 deliveries to spare.
The chase was far from straightforward for Hobart, who crashed from 0-51 to be 5-71, then 7-95, before lower-order pair Kathryn Bryce (34no) and Lauren Smith (16no) put on 44 unbeaten for the eighth wicket.
The pair helped Hobart (10 points) leapfrog Perth (nine) into fourth spot on the ladder and the box seat for a finals berth.
The sixth-placed Sydney Sixers (eight points) remain an outside chance to edge the 'Canes out of the four.
They will need to beat Brisbane Heat at Allan Border Field on Monday, the competition's last fixture, by a large enough margin for their net run-rate (-0.367) to rise above Hobart's (+0.189).
The Hurricanes raced past the half-century from five overs before Elyse Vilani (11) was trapped lbw by Amy Edgar.
Sophie Devine (4-26) took a terrific outfield catch to get rid of the dangerous Lizelle Lee (44 off 22 balls), then picked up Heather Graham (1) and Suzie Bates (0) in her second over.
Devine then castled Tabitha Saville (11) and Molly Strano (0) in her third over to have the 'Canes seven-down in the 13th over before Bryce and Lauren Smith saved the day.
Earlier, Devine (28) and fellow international veteran Beth Mooney (50) were in total control with the bat, taking the Scorchers' total to 2-105 in the 14th over, before the wheels fell off completely.
Amy Smith took a sharp catch to get rid of Devine, before capturing the key wicket of Mooney who spooned a catch to Bates.
Spinners Amy Smith (3-17) and Lauren Smith (2-24) plus four run-outs led to Perth's dramatic demise.
Earlier, the Melbourne Renegades crushed the Sydney Thunder by nine wickets to take top spot on the ladder.
The Thunder were bowled out for 133 in 19.1 overs with Renegades spinner Sophie Molineux snaring 4-23 at Melbourne's Junction Oval.
The Renegades then raced to 1-137 from 14.2 overs with opener Hayley Matthews blasting 60no from 37 balls and Molineux capping a stunning all-round performance with an unbeaten 42 from 29 deliveries.
The Renegades moved to 14 points, taking top spot from the Thunder (13 points).
Brisbane Heat (12 points) will need a big win over Sydney Sixers on Sunday in the last match of the minor rounds to jump ahead of the Renegades.
The Renegades' Matthews (seven fours, two sixes) and Molineux (seven fours, one six) made light work of the run chase with an unbroken 95-run partnership.
The Thunder earlier struggled to gain traction with the top-order batters failing to capitalise.
Phoebe Litchfield top-scored with 30, hitting six fours from her 17 deliveries while No.7 Sammy-Jo Johnson made 21 from 19 balls.
Openers Georgia Voll, Chamari Athapaththu and Georgia Adams all made 11, as the Thunder slipped from 3-95 in 12th over and lost their last seven wickets for 38 runs.
The Renegades' Molineux was superb with her four-wicket haul accompanied by a dozen dot balls in her four overs.
Georgia Wareham (2-20) and Deandra Dottin (2-24) also claimed multiple wickets.
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