You can forgive Cris "Cyborg" Justino for thinking she could walk through Amanda Nunes' punches. After all, she'd been doing just that to every woman she'd fought for more than 13 years. Twenty victims had fallen to her mighty hands, 17 of them by knockout. 

But Amanda Nunes (17-4) is a different kind of opponent.

She didn't just stop the domineering Cyborg in her tracks. She knocked her down and out in an astounding 51 seconds, looping overhand rights and destroying the myth Cyborg had built over a long, glorious career in mere moments.

"Just haymakers," UFC announcer Joe Rogan exclaimed, forced to resort to sound effects when words alone wouldn't do. "Boom! Boom!"

Two years ago, Nunes made the legendary Ronda Rousey look like last year's model, demolishing the most dominant bantamweight in UFC history in just 48 seconds. Rousey looked shocked by Nunes' combination of power and speed and never quite recovered from being hit by a woman with legitimate knockout power in her hands for the first time.

Cyborg, to the surprise of many, also appeared overwhelmed by Nunes' athletic gifts.

"I think when we're gonna be face to face and I start touching her, she's gonna feel the difference," Cyborg told Thomas Gerbasi of UFC.com before the fight. "I don't think she ever fought somebody like me."

Instead, it was Cyborg who was stunned by differences in speed and technique. Cyborg is so used to being the bigger, stronger woman that Nunes' initial hard leg kick and powerful right hand put her in unfamiliar territory and forced her hand.

Cyborg is best as a counterpuncher and surely wanted to wait for her opportunity to strike. But Nunes' aggression prevented that plan and brought out Cyborg's own wild side. Rousey had retreated into a shell when faced with Nunes' powerful, long punches. Cyborg, instead, stood her ground and attempted to give as well as she received—and paid a heavy price for her reckless charge into the Lioness' den.

"She was too fast for her," former UFC champion Dominick Cruz said during the broadcast. "She was too fast for Cyborg. That was the difference. Cyborg was throwing with reckless abandon, and Nunes was able to strike right down the middle over and over again."

Most fighters had all but given up before they ever stepped into the cage with Cyborg or Rousey. Their intimidating reputations and impressive resumes made the result seem all but inevitable. But Nunes seems at her best when the lights are brightest and the opponents are particularly formidable. Against both of the previously mentioned former champions and crowd favorite Miesha Tate, she became a Brazilian wrecking ball, leaving no doubt about who the better woman was, each time securing a first-round victory. 

Already the UFC champion at 135 pounds, Nunes stepped up 10 additional pounds to claim a second title belt. No other woman in UFC history has ever managed this. After the fight, Nunes, despite being just 30 years old, was already thinking about her legacy.

"Dana," she said, addressing UFC President Dana White, "Now I have to be in the Hall of Fame."

That honor, at this point, is almost an afterthought. With five consecutive victories in title fights and an overall UFC record of 10-1, her record is undeniable. Even her lone loss, against former title contender Cat Zingano, came after delivering a tremendous beatdown in the first round before running out of steam. Rousey and Cyborg were widely considered the top champions in the sport's short history. Nunes has now destroyed both, causing damage not just physically, but to their legacies as well. 

Nunes calls herself a lioness. But after a win this dominant, another animal comes to mind: the G.O.A.T. 

Jonathan Snowden covers combat sports for Bleacher Report.