The form guide predicts a draw in the four-day contest between Australia and England. Rain threatens to dampen the occasion on Saturday, while the past four women's Tests played across the world have all failed to produce a winner.

Yet fascinating sub plots underpin what could well prove the decisive contest in this Ashes where rain has so far proven itself more of a pest than Covid.

Beth Mooney is set to bounce off the canvas and play 10 days after breaking her jaw.

The selection shackles will be off Ellyse Perry after she wasn't picked for last week's T20s. Her last Ashes Test produced a superb century, and the one before that delivered an unbeaten double ton.

Then there's luckless England, who must avoid defeat just to stay alive in the series after a loss and two washouts in Adelaide last week.

Stuck in strict isolation for two weeks before leaving England, captain Heather Knight and her squad have found themselves wading treacherously through an Australian summer cloaked in La Nina.

"Come to Australia, expect a bit of sun," a frustrated Knight said on Wednesday.

The four-day Test match remains the most uncharted of territories in the women's game.

Perry has played nine such fixtures (and done quite well, scoring 693 runs at 86.62).

Australia's most experienced men's player, the ex-Manuka Oval groundsman Nathan Lyon, has played 105.

This will be Australia's second Test in four months, after a pre-Summer draw against India on the Gold Coast.

Prior to that they played out an Ashes draw in 2019, two years after the drawn Test against England at North Sydney Oval.

Not since 2015 has Australia won a Test, a 161-run triumph at Canterbury which allowed them to win back the Ashes.

That was Matthew Mott's first Test as Australian coach, and he formed a pretty quick opinion on how best to improve the concept in the women's game.

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"If you're going to do it, I think you do it with five days," Mott said.

"Every Test match I've been involved with we've had some play lost due to rain, even the one at Canterbury that we won we lost pretty much a full day's play."

Mott's opinion is one shared by Knight - an eight-Test veteran whose 481 runs at 37 prove she's also capable of batting for extended periods in the longer format.

"I'd love five-day cricket, when we play Test matches so rarely, I think it's important that we have those five days, because weather intervenes," Knight said.

"The last two women's Test matches, us against India and Australia against India, would've been set up for a nice finish if we'd had those five days."

Veteran teammate Katherine Brunt, on the verge of her 13^th Test, has radically suggested shortening the pitch to increase excitement levels in women's Test matches.

She also floated the idea of playing with Dukes balls, like the English men do when hosting Test matches on home soil - the idea being a Dukes ball would offer the bowling side a more active seam for longer into an innings.

"There's little tweaks that can be made, I definitely don't think the pitch should be shortened," Knight said.

"I do think a Dukes ball would make women's Test match cricket a bit better, particularly when you get on a pitch that's quite flat.

"The lower pace in the women's game generally can make it hard to score and hard to take wickets. The pitch is key, the ball is key."

And tactics are key. The scarcity of the product provides the ultimate challenge for players whose domestic calendar is a mixture of 50-over state games, and a busy T20 women's Big Bash.

After a summer of fast scoring and attacking bowling, international stars are expected to occupy the crease for long periods, while sometimes trebling their workloads with the ball in a single innings.

Push too hard, and it can backfire. Not hard enough, and the prospect of another draw awaits.

"We play a lot of one-day cricket, so we don't want to take our game too much away from that because that's what we are best at," Australian captain Meg Lanning said.

"It's just adjusting to those difficult times both with the bat and ball, being a little bit more patient perhaps than we normally would be in the shorter formats.

"The best way for us to go about it is to play our natural games as much as we can."

Lanning's side is in the box seat after her unbeaten 64 in last week's Ashes opener in Adelaide helped Australia to a crushing nine-wicket win.

The two subsequent washouts left Australia leading the series 4-2 on points. A win would ensure at minimum a drawn series, and thus the holders Australia would retain the urn, irrespective of the remaining three 50-over matches.

But Mott wants more than just retaining the Ashes - he wants to win the series.

"There'll still be plenty on those last three games as well," Mott said.