(CNN) When Tia-Clair Toomey takes the field at the 2019 CrossFit Games later this summer, she will do so as the overwhelming favorite to claim the title "The Fittest Woman on Earth" for an unprecedented third straight time.

The 25-year-old Australian former sprinter began her dominance of the sport in 2017 when she edged out compatriot Kara Webb (now Saunders) by the narrowest of margins. Twelve months later, she dominated the field to claim her second title and has looked unbeatable ever since.

Beside her throughout has been her coach, and now husband, Shane Orr -- the two having married shortly after her first CrossFit Games victory back in 2017.

While it's not uncommon for athletes and coaches to fall in love and marry, Tia and Shane's relationship may be somewhat unique in sports, having met long before they had even heard of CrossFit, when they were just teenagers competing at a team triathlon back in Australia.

Tia-Clair Toomey is bidding to become "The Fittest Women on Earth" for the third consecutive time.

'My whole strategy changed'

"I was on my bike waiting for my tag to start my leg on the ride," Shane recalls.

"Tia comes out of the water... takes off her [swimming] cap and nods her head trying to get water out of her ears. For me that was like a Baywatch moment... everything happening in slow motion.

"I was intrigued by this person coming out of the water in the first place, a female and she's beautiful."

As she rode off ahead and Shane waited for his teammate, he put together a plan.

"All I knew was, 'Right, if I catch up to her, just look, look comfortable, look good.' My whole strategy changed. It went from trying to place well to trying to place near her."

Knowing how the course doubles back on itself, Shane knew eventually they would pass each other on the run stage. Shane's plan was to make sure he looked good no matter how tired he felt.

But after running strongly for as long as he could, eventually his exhaustion kicked in just at the wrong time.

"I can't hold this. I've just got to have one good breath. So I start trudging. I'm looking down and I hear, 'Keep your head up. You can do it!' I look up and it's Tia," he said.

"She's encouraging me to get back into the race when my whole game plan was to inspire her and make myself look good."

JUST WATCHED Sara Sigmundsdottir: CrossFit star's comeback Replay More Videos ... MUST WATCH Sara Sigmundsdottir: CrossFit star's comeback 02:55

'My secret weapon'

That embarrassing moment did not stop the two from eventually getting together. At the time, Tia was training to become a sprinter. Shane would help her dad with the training, holding the stopwatch and keeping a track of her times. A decade on and Shane is still holding that stopwatch.

Now as her CrossFit coach, a role he learned specifically in order to help her train, the partnership has been incredibly successful.

Not only has Tia won two CrossFit World Championships, she also claimed gold in weightlifting at the 2018 Commonwealth Games and qualified for the 2016 Olympic Games -- something Toomey credits to their relationship.

"I feel like Shane's my secret weapon," she said.

"He obviously knows how I'm feeling and I can be very open with him, but he's also going to tell me when I'm wrong and he's not afraid to tell me to [toughen] up.

"There are definitely times throughout training or competition when you do need that hard chat. I think that Shane has definitely been able to help me grow, not only as a person but as an athlete and a competitor and it's been pretty incredible."

These hard chats may be difficult when you're married to the person you coach, but Shane seems to have found a balance.

"I don't put out on the line," he laughs. "But I am stern, to say the least."

JUST WATCHED Inside CrossFit's secret gym Replay More Videos ... MUST WATCH Inside CrossFit's secret gym 01:44

For now, Tia cannot see herself being coached by anyone else and Shane has no plans to continue coaching after Tia steps away from the sport.

However, if the two have kids and Shane were to become their coach, the two have already worked through how that may work.

"Oh, I will feel so sorry for them," Tia said, imagining the scenario.

"I'll probably side with them because I know exactly what they're going through."

Defending himself, Shane jokingly adds: "I'm kind of a good person. If you get to know me."