The all-time series between New Zealand and Australia women's rugby seems a bit like an older child picking on a younger sibling.

The elder child may let the younger one feel good about themselves sometimes, but it will never let them get ahead.

The Black Ferns have reigned supreme in the nearly three decades the two rugby-proud nations - who sport a competitive rivalry on the men's side - have played each other in women's rugby, though there have been some glimmers of hope, including recently, that the Wallaroos finally may be able to clear their New Zealand-shaped hurdle once and for all.

With Australia having two chances to finally upend New Zealand as part of the Laurie O'Reilly Cup this month, where each country will travel to each other's home in a two-test series, the Wallaroos will get to meet their adversaries face to face on successive weekends. 

The Black Ferns also have a Women's World Cup to defend later this year on their home soil, and that type of pressure is one heck of a motivator.

What is there to watch out for as Australia and New Zealand play Saturday (in Christchurch, New Zealand) and Aug. 27 (in Adelaide, Australia) in a high-stakes World Cup tune-up? 

Here's a peek at what both the Black Ferns and Wallaroos bring to the table. Both matches will be streamed live on FloRugby.

New Zealand

Current World Rugby Ranking: Second

The lowdown: If New Zealand rugby fans are getting tired of watching the All Blacks go on a horrendous run of form as of late, perhaps the Black Ferns could be of assistance. After all, New Zealand's women's rugby team has never ranked lower than second in the Women's World Rugby Rankings since they were introduced in 2003.

The team also has won five of the six Women's Rugby World Cups officially backed by World Rugby (since 1998). 

Though world No. 1 England is on a historic 23-match winning streak and has been the crown jewel of the women's game for several years, the Black Ferns do host the upcoming World Cup in October for the first time and have only lost twice on home soil since 2001. 

Plus, they love to bully Australia, having never lost to the Wallaroos across 20 matches dating back to 1994. 

Coming off a Pacific Four Series title in June in which it walloped Australia, Canada and the United States in quick succession, the 33-player New Zealand squad selected by coach Wayne Smith for the two Wallaroos tests to come is - as per usual with the Black Ferns - loaded. 

All-time caps and scoring leader Kendra Cocksedge is still going strong at age 34, with the Matatu and Canterbury halfback having featured for her national side more than double the amount of times as anyone else on the roster. She has 60 appearances to her name. 

Plenty of veterans from the 2017 World Cup-winning team, including loose forward Charmaine McMenamin, inside back Victoria Subritzky-Nafatali and others, are in the mix and looking to get some tune-up time on the pitch prior to kicking off their bid for yet another repeat World Cup title.

With how good England is at the moment, it may be easier said than done, but the two-test series against an old rival should make for a decent way to iron out any wrinkles before then.

Australia

Current World Rugby Ranking: Eighth

The lowdown: Yes, Australia's women's national rugby team has never beaten New Zealand. Yes, the Wallaroos have never quite reached the heights on the rugby world's biggest stages like the Wallabies have. Yes, Australia is on a painful four-game slide heading into another two matchups against what's long been considered its bogey team. 

But, as only 12 nations reach the Women's Rugby World Cup every time it's held (compared to 20 for the men's tournament), getting there in the first place is a huge achievement. 

Australia, which has qualified for every World Cup it has entered (including the one coming up later this year), keeps taking on the elites in hopes that one day it can crack through and join them. 

The Wallaroos have come agonizingly close on several occasions to beating the Black Ferns, and their 23-10 loss to the Kiwis in June as part of the Pacific Four Series - in New Zealand, no less - was Australia's closest result against the five-time world champions since a six-point defeat in July 2008 in Sydney. 

Could that arm's-reach result be the boost of confidence Australia finally needs to finally slay the dragon? It's anyone's guess, but the Wallaroos have got to feel like they have two proper shots to test that theory this time around. 

Queensland Reds flanker Shannon Perry will captain the side, but coach Jay Tregonning also picked an intriguing uncapped player to his 32-player roster in Bienne Terita, who has been strong for Australia's women's national sevens team recently. 

She's one of six players who'll be looking to earn a first national-team cap against the Black Ferns, with Reds prop Liz Patu, born in Auckland, leading the way in terms of veteran leadership with a team-high 28 caps, one of which included a try scored against her nation of birth June 6.