A basic martial arts hold that Ronda Rousey learned as a troublesome teenager has been the catalyst for her pioneering fighting career and emergence onto Hollywood’s silver screens.
The armbar - where Rousey traps her victim's arm between her own legs and torques the elbow unnaturally - led her to the inaugural UFC women's bantamweight title but was learned in her education as a judo competitor.
Jimmy Pedro, a two-time Olympic bronze medal winner, schooled the young Rousey at judo until the conclusion of her own bronze medal winning effort in Beijing in 2008. Their relationship ended when Rousey turned her back on the sport to pursue the little-known prospects of women's MMA but Pedro has been watching ever since.
"It's rewarding to me when I see her win UFC fights with that armbar," Pedro told Sky Sports.
"Ronda drilled that thousands of times while she was in my school. She was learning the armbar technique for the first time aged 16.
"For seven or eight years, we drilled that position inside and out. All of my athletes know how to do that technique, how to defend it, and how to finish it.
"Unquestionably I recognise my judo in her MMA game. Specifically, the way that she enters the armbar from the top, the way she rolls, then she way she finishes her opponent."
Of her unbeaten 12 fights, the first eight and a total of nine have ended with opponents submitting to Rousey's armbar, occasionally with their arm in such a grotesque position it was close to breaking.
But her evolution into the dominant force seen today - she will next defend her gold against Holly Holm at UFC 193 on November 14 - is also down to skills learned through Pedro's judo tutelage, he says.
"Ronda's a lefty - that means she stands left-sided in judo and MMA," he explained. "A lot of the throws she does are predominantly left sided.
"We are strict about our gripping system in my school, and a lot of the positions that Ronda gets in have been learned here."
Pedro first crossed paths with Rousey when she was the 11-year-old daughter of a judo world champion. He would eventually welcome the teenager to his school and coached her throughout her Olympic pursuit - but insists that Rousey was never the unstoppable force seen in the UFC Octagon.
Pedro said: "In judo she got a decent amount of wins by armbar but she couldn't do it to everyone. She wasn't a gold medal winner in every event. She never won the world championships.
"In the Olympics, she took a bronze once. But she wasn't dominating the major events.
"She was always top five in the world but she wasn't dominant like you see now.
"She was a rebellious teenager who rebelled against her mother. She was dedicated to judo but she wasn't disciplined like she is today."
After winning bronze as a 21-year-old in Beijing, Rousey revealed in her autobiography that she struggled financially despite her sporting accolades. She fell out of love with judo and went her separate ways with Pedro.
She found that her judo skills made her dangerous at MMA but it wasn't until her seventh fight that she became the first women to fight in the UFC when she beat Liz Carmouche. Pedro, who didn't approve at first, has watched her star rise more than he ever imagined.
"She was tired of judo, didn't want to grind for another four years before the Olympics, and wanted something bigger," he said.
"She was a cagey fighter; there are only a few people who truly hate losing more than they enjoy winning.
"What's happening today is that you have Ronda, who is a devastatingly-trained assassin, fighting against girls who have only recently started trying to catch up to something that she's practiced for her whole life.
"Their instincts just aren't there."
Ronda Rousey next defends her world title against Holly Holm at UFC 193 on November 14.