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Whether you look back at UFC 269 as the night Julianna Pena won the women's bantamweight title or as the night Amanda Nunes lost it to snap a historic 12-fight win streak, we all can agree it was just about the most shocking upset in the history of the sport.  

Eight months later, following a stint as rival coaches on "The Ultimate Fighter," the pair of 135-pound titans will touch gloves again in Saturday's much-anticipated rematch, which headlines a UFC 277 pay-per-view card in Dallas.  

Assessing whether the upset was more a result of what Pena did or what Nunes didn't after instantly tapping amid exhaustion to Pena's rear-naked choke in Round 2 is probably more dependent upon the eye of the beholder.  

Pena (11-4), a massive betting underdog, did succeed in luring Nunes (21-5) into a wild brawl just one round after deftly gassing her out on the ground during a series of scrambles that included Nunes coming close to applying a choke. But Nunes, who left American Top Team shortly after the loss to start her own gym, certainly looked like anything but the G.O.A.T. throughout the fight, which led many to question if success and life as a new mother had dulled her focus and edge.  

One thing about their first meeting and how it might affect this weekend's rematch seems to be undebatable: Nunes surrendered her crown on what was easily the worst performance of her elite run whereas Pena captured the title on her best night, by far.

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So, can lightning strike a second time in the same place or are the oddsmakers right in retaining Nunes as the betting favorite to right the wrong in the same manner Georges St-Pierre once did to Matt Serra in their second meeting? Or does the mentally tough Pena simply have Nunes' number thanks to a mental edge she feels she has quietly held over "The Lioness" for a number of years?

"I think I have always had the mental edge when it comes to Amanda," Pena told "Morning Kombat" in April ahead of the TUF premiere. "I have been calling out this fight for the last five years and she has always made an excuse to find a way to get out of every fight that we had. Obviously, the way I say things and how I approach has bothered her and she has made that very clear." 

If Pena, 32, has sounded crazy at all in the leadup to either fight, the native of Spokane, Washington, who goes by the moniker of "The Venezuelan Vixen," says it's by design.  

First off, she's a fighter and, according to Pena, "fighters are crazy, we fistfight for a living. Obviously, there is something wrong with me. We choose getting punched in the face for a living. [You want] crazy? We got that."

But there's a part of Pena that also comes off as a bit of sly fox who hides her genius behind a much more boisterous and seemingly unhinged exterior. Need a sound bite of cleverly crafted trash talk? Pena typically has your back.  

Part of that appears to be Pena's way of psyching herself up, even when things haven't always gone her way throughout a career marred with injuries and setbacks that slowed her rise, including a nearly two-year break that included the birth of her daughter in 2018. So hearing Pena call out Nunes for avoiding her for the previous six years must be taken with a grain of salt, especially considering Pena was just 2-2 in her last four fights before facing Nunes, including being stopped each time she stepped up in class against Valentina Shevchenko andGermaine de Randamie.

What we ended up learning about Pena's version of crazy, however, is that it's also spiked with the feeling that she knows something everybody doesn't and is fueled by that secret. At UFC 269, that secret turned out to be her combination of unshakable self-belief and a never ending gas tank to maintain such a breakneck pace, both of which get filed under the category of elite intangibles.  

"When you know how hard you have been working and grinding, nobody can take that away from you or say that you are a liar and are unprepared," Pena said. "I know how hard I worked. It wasn't that I was crazy for believing in myself, it's just that I know what I did. I knew what it took and I knew I was not going to be denied that night, just like I will not be denied [in the rematch]. 

"It wasn't so much crazy as it was hard work." 

So if Pena doesn't quite have the exact same skill set as Nunes or proven track record, which is a large part of why she remains an underdog, will any potential edge in mental toughness be enough to outlast Nunes in the trenches a second time?

Pena says yes, pointing to the "really big and scary dog" inside of her and that mentality which says, in her own words, "I am literally going to rip your face off if it's the last thing I do." But the odds of the rematch being a much more technical affair, especially if Nunes is able to make Pena chase her while countering from distance, remain strong. Just as strong as an expected Nunes win might be should she be able to keep the fight standing and not risk dumping her gas tank within grappling exchanges.  

Again, Pena points to the work she has done in the gym being enough, regardless of how much the 34-year-old Nunes claims she is reborn after such a shocking loss.

"If you are crazy enough and know the work that you have put in, it's easy to say, 'Come one, come all. I'll take you all on at the same time. Who wants some? Come get some,'" Pena said. "I don't care if you weigh 160 pounds or 120 pounds, I will fight if you get in front of me. There is a dog that lives inside of me and I will not be denied. No matter what happens, you are going to remember that you were in a fight with me. Period." 

Pena essentially bullied the bully in her victory over Nunes by standing up to huge power shots in Round 2 and walking through them with a series of educated jabs and short left hooks that staggered her exhausted foe and made Nunes weak enough to be finished. And she claims that their time together as TUF coaches only exposed how much of a "diva" Nunes is and how in her head Pena continues to be.  

This time it will need to come against a version of Nunes, a native of Brazil, who will have no excuses but to train harder than she ever did before to prevent Pena from finding the ripcord to her parachute.  

If the rematch is fought under the terms Nunes typically controls, the odds remain in her favor. But if chaos prevails a second time, it's not as easy as one thinks to count Pena out from pulling off a second straight triumph of the human spirit while proving just how dangerous the power of self-belief, when it's paired with peak cardio, can sometimes be.  

"I think that I lit a gas can of fire right underneath her behind and she is going to be more focused than she has ever been," Pena said. "I think she's going to be the best Amanda that she has ever been. That's funny because that's what she said she was going to do the first time. 

"Do you think that when you beat the GOAT that you become the goat slayer? I might be the goatslayer. I beat Amanda and I'm going to beat Amanda again. If they want to put me in the GOAT conversation, that's fine but that's not a cap that I want to wear. That's not a hat that I feel like suits me because it puts so much added pressure that I don't want. Just call me Julianna Pena, instead, and know me as one of the best female fighters in the world."