Medium-pacer Sarah Aley took four wickets as the Sydney Sixers defeated the Adelaide Strikers by 17 runs in Friday's WBBL semi-final.
Chasing 139 runs to win, the Strikers suffered a horror top-order collapse, losing 6-3, before reaching 9-121 at Adelaide Oval.
The Sixers will seek consecutive titles when they play the Perth Scorchers in Sunday's final - a rematch of last year's decider.
The Strikers lost their initial six wickets in an 18-ball span to cruel their run chase.
Aley took four of those, starting the rot by snaring wickets with her first two balls.
Teammate Kim Garth claimed two wickets in the next over before Aley made another double-strike in the following over.
Aley had stunning figures of 4-1 after her initial two overs.
"I don't think I have had figures like that before," Aley said.
"For me, it was just a matter of making sure that I was sticking to my plans and that was to attack the stumps."
Aley finished with 4-18 from four overs, her feats coming after Ashleigh Gardner had top-scored with 72 as the Sixers posted 5-138.
"We thought we needed quite a few more runs," Aley said.
"Obviously, in a final, things are a bit different but runs on the board - there is always pressure."
Gardner faced just 45 balls in a knock featuring six sixes and five fours and helped Sydney recover from the loss of opener Alyssa Healy (two) from the ninth ball.
After a cautious start - the Sixers were 1-9 after four overs - Gardner launched as captain Ellyse Perry (16 from 31 balls) farmed the strike.
The Strikers stemmed the flow and conceded just eight runs in the final two overs, with Sophie Devine taking 2-21.
But Adelaide's batters spectacularly collapsed: from 0-20 after three overs to 6-23 after six.
Tammy Beaumont (50 from 46 balls) offered resistance but the Strikers fell well short of advancing to their first final.