Whether it was against each other as children where they would sprint around their home in the quickest time possible, or against opposing AFLW teams, helping Brisbane to a third straight preliminary final with a contagious desperation that inspires their teammates.
If it's a competition, the Svarc sisters are in.
Two of five siblings that grew up on the family's farm on the Murray River near Corowa, 45 minutes west of Albury, the pair were born into adventure.
And although they wouldn't take up competitive sport until their mid-teens, that didn't stop them from wanting to one-up each other at everything.
"We had a massive garden and all this lawn area to play games," Ruby told womens.afl.
"We played soccer, we played badminton, volleyball, cricket. We were kind of out of town, so we had to make our own fun.
"It was always competitive.
"Whether it was games, board games, card games, racing each other around the house, who could do it quickest. We'd race each other on bikes.
"We were always trying to outdo each other – who could do the longest handstands."
That "massive garden" Ruby speaks of is a 400-acre property that runs poultry and cattle and harvests mixed crops.
"We had to be fairly creative. We'd say, 'We're bored' and mum would say, 'Go outside'," Cathy continued with a laugh.
"We'd go on little adventures around the farm, or we'd play games, two v three. That's what I remember. We'd be outside playing all the time."
With older sister Simone and younger siblings James and Caroline to fill out the numbers – the five were all born in a seven-year span – there was always something happening.
Cathy and Ruby were always good athletes, as explosive at sports day sprints as they are now on a football field, and once they hit high school, convinced their parents to play club netball, the first time they would be put into a structured environment.
Ruby says it was here, as a 14-year-old, that she fostered habits that would last a lifetime.
"My first two years we lost every single game," she said.
"My third season we won our first game maybe five rounds in and the euphoria we felt winning was amazing.
"We always went in as hard as we possibly could no matter what the score was.
"For me, as a footballer or athlete, if we're down on the scoreboard, it doesn't bother me. There's always that determination to win, no matter what the score is.
"We're not put off by the score if we are losing. It won't change the way we play, it only actually makes me play harder."
Ruby left home at the age of 19 and headed to Melbourne to finish her university degree and begin working, while Cathy would find her way to Geelong to begin life as a physiotherapist.
It was here their life would take a huge twist.
With the AFLW in its first season in early 2017, the sisters would sit at Cathy's place and watch on.
Their extended family were into Australian Football, so they'd always been exposed to it and had an interest, but never had an opportunity to play.
"It sparked a bit of interest," Cathy said. "We thought, 'Jeez, that'd be pretty cool'."
With the seed planted, Ruby would head along to St Mary's Salesian in the VAFA to give the sport a go. She loved it instantly.
At almost the same time, Cathy had moved to Brisbane to continue her work career and headed along to Wilston Grange.
"Ruby had just started and told me to have a go. I just needed a bit of a push," she said.
"I didn't know anyone there. It was the first time in my life I'd rocked up not knowing anyone – I'd only been in Brisbane a month or two.
"I rocked up at Grange and they welcomed me pretty quickly. Luttsy (Kate Lutkins) was there, Shannon (Campbell) was there. It opened some opportunities for me."
Amazingly, both sisters won premierships in their first seasons. Cathy would be drafted by the Lions in 2019, with her explosive pace, running power between contests and thirst for laying tackles eye-catching.
Ruby would head north 12 months later after starring for Essendon in the VFLW, finishing runner-up in the League best and fairest.
It took a year on the Lions list together before they'd run out in the same game – round three against Carlton in season six – but since then they haven't missed a beat.
Cathy, who is about to turn 31, is a critical part of Brisbane's midfield alongside Emily Bates and Ally Anderson, while her 29-year-old sister has slotted into the forward line with ease, using her speed to apply relentless pressure and create opportunities both with and without the ball.
Their impact can be summed up in one play against Essendon in round six.
With the ball around 50m from Brisbane's goal, Ruby laid the perfect tackle on her Bombers opponent, and when the ball spilled free, Cathy was there to swoop, gather, run 15m and kick accurately as the three-quarter time siren sounded.
The next chance for the pair to compete comes against Adelaide at Metricon Stadium on Friday night.
One more win and the girls that spent the early years of their lives trying to beat each other on the vast spaces of a Corowa farm might just get the chance to lift a premiership trophy together for the first time.