The Sixers and Scorchers clash at Adelaide Oval on Sunday in a rematch of last year's WBBL grand final.

Sydney won that game and strike bowler Sarah Aley says disrupting Perth's top-order batting will be vital to repeating the feat.

While Sydney topped the table in this edition of the tournament, the Scorchers beat them twice in their minor-round meetings.

"The games against the Scorchers, they are probably a couple of times when we missed out on taking early wickets," Aley said.

"With them, that is crucial.

"Obviously Elyse Villani and Nicole Bolton have been batting really well and are keys in their line-up and they have got some really strong players in their middle order as well.

"So for us, it's making sure we take early chances.

"We have seen in the last few games that when we do that, we have got on a bit of a roll and been able to put a squeeze on."

Aley will be a pivotal player in that template after her semi-final heroics - she claimed four wickets in a 17-run win against the Adelaide Strikers.

Aley snared wickets with her initial two balls and, after two overs, had remarkable figures of 4-1.

That took her tournament total to 22 wickets, second only to Perth's Katherine Brunt (23 wickets).

The Scorchers' Villani is the leading run-scorer with 519 runs and her opening partner Bolton is third with 477.

And while cheaply dismissing that duo is central to Sydney's plans, Aley said the Sixers would also look inward.

"We just look at ourselves mostly and make sure that we're doing the things that we want to do," she said.

"With the bat we probably didn't score as many runs as we would have liked (in the semi-final) so that is an area we will look at - making sure we're scoring off as many balls as we can and just eliminating the dot balls.

"And then making sure we're nice and sharp in the field, I think those things are what is going to keep us in good stead."