Julianna Pena -- MMA's 'Venezuelan Vixen' -- wants to fight the good fight

Women's bantamweight contender Julianna Pena (blue gloves) has yet to lose a UFC fight in her career. Troy Taormina-USA TODAY Sports

In mixed-martial arts fighting, the aim is basic: to subdue or overcome an opponent by whatever allowed means one can.

It's something Julianna Pena has excelled at during her UFC career. Pena believes she should be the next female bantamweight fighter in line for a title match. The delay is making her impatient.

"It's politics," Pena said. "It's a popularity contest. Right now, we're living in the Ronda Rousey show and whatever that spoiled little princess wants, she's going to get. Everyone else gets put back on the back burner in the meantime."

In some ways, Pena's words echo those of Brazil's Jose Aldo, who recently claimed that Conor McGregor, another popular fighter, "is in charge of the UFC." Both Pena and Aldo are essentially accusing the UFC of giving certain fighters unfair privileges regarding when and who to fight.

Though McGregor and Rousey have large fan bases, one key difference between the two is that Rousey has not fought since losing to Holly Holm last year, while McGregor defeated Nate Diaz in August and is fighting Eddie Alvarez in November. Rousey's defeat presaged more turnover in her division. No female fighter has successfully defended the bantamweight title since Rousey lost it. Holm gave up the title to Miesha Tate, who then was defeated by the current champion, Amanda Nunes. Pena is convinced she has paid her dues and deserves her own shot at the championship.

"It's a popularity contest. Right now, we're living in the Ronda Rousey show and whatever that spoiled little princess wants, she's going to get. Everyone else gets put back on the back burner in the meantime." MMA fighter Julianna Pena

"I have taken the tough fights," Pena explained. "I've beaten the top-ranked girls. I beat No. 3, Cat Zingano and I took her ranking and [Valentina Shevshenko] jumps ahead of me, who already lost to the champion and they want me to fight her? I already fought No. 3 and took her out and you said I was going to get a title shot then."

Pena rejected a proposed UFC 205 bout against Shevshenko, who recently defeated Holm.

"I value myself as a fighter; I'm unbeaten in the UFC Octagon," said Pena. "Until they have a signed fight for Ronda Rousey or Amanda Nunes, I'm not going to make a move."

Part of Pena's willingness to hold out for a fight that matters comes from lessons learned the hard way in her journey through mixed-martial arts. She got a late start in the sport, beginning at the age of 19.

"My sister invited me to a woman's cardio kickboxing class," said Pena. "It was love at first punch. My coach said I was a natural and I just kept coming back to his cardio kickboxing classes. They invited me to stay for the MMA classes."

Though she realized that her chosen sport was dominated by those who usually had years of training in some sort of martial arts discipline before switching to MMA, Pena persevered.

"I'd go every night and train," Pena said. "A lot of parents start their kids off in karate or taekwondo or judo, or stuff like that. I'd never done any sort of combat sport before."

Determined to catch up, Pena didn't let her lack of finances slow down her training.

"I couldn't pay for my gym dues to train there, so I cleaned the gym every single day in order to pay for my dues so I could train," said Pena. "I just kept doing that progressively for about six months before I took my first fight."

The youngest in an active family, Pena did have in her favor a generally athletic background that improved rapidly with regular training.

"[My coach] did talk about how some kids who started doing combat sports at a younger age had more injuries and they didn't let their bodies develop into adulthood before fighting and had several problems," Pena said. "He was never worried about the fact that I hadn't learned anything prior. He just kind of molded me into the fighter that you see today."

Though her coaches spotted her natural talent quickly, Pena's family wasn't so convinced about a profession in MMA.

"At first, they weren't all OK with it; my dad doesn't want to see his baby girl get punched in the face," Pena explained. "They are all supportive now and they all think now that it made a lot of sense, the career that I chose."

Pena's family has inspired her UFC nickname.

"When I think of being Venezuelan, I just think of my dad and how his story is so significant, coming to America and how he immigrated here," Pena said. "It makes me very proud to know that I am Venezuelan and that those are my roots."

The "vixen" part of her name also comes from that heritage.

"Venezuelans are extremely vain people," laughed Pena. "They love to dress up. The women and the girls there are raised up as little princesses from the moment they come out of the womb - divas."

Pena recalled female relatives in Venezuela telling her not to smile when she visited, in order to avoid wrinkles. The risk of putting her looks in danger while fighting isn't one she worries about much, though. She confesses to enjoying dressing up on her days off.

"It's like beauty and the beast. You go from one extreme of being a beautiful woman and no one would ever assume that you're a fighter, to being ruthless, an absolute monster when you're getting in the cage. It's a major contrast, but I feel that it empowers women, to know that they don't have to be just super-girly. It's something that I prove to myself every time I get in that octagon - that I can do it. Si se puede!"

Though sometimes exasperated with UFC management, Pena is also grateful that the organization made the choice to open a women's division three years ago. It came at a crucial time for her. After dominating opponents in her early fights, she didn't prepare well and lost two in a row. Pena nearly quit MMA, but then was invited to and won the UFC's Ultimate Fighter show. After that came the brutal grind to rehab and rebound from a devastating, career-threatening knee injury. Pena credits her mental toughness for her comeback, which took over a year.

"It's not something that you can teach. Some people are going to quit and give up; other people are not going to tap when they get their arm broken. They'll keep fighting with one arm."

Unbeaten now in all her UFC fights, Pena wants a title shot badly.

"I want the big fights," Pena said. "That's seven girls in a row that I've beat, you know."

She pointed out that in the 115 pound division, the Ultimate Fighter winner was immediately given a championship belt, and that fighters who won against fighters Pena had already defeated in her edition of the show, have also gotten title shots.

"I feel like it's not fair and it's not cool. I have proven myself time and time again."

Read the Spanish-language version of this story here. Also, join One Nación for a special that will air on Oct. 12 at 7 p.m. ET on ESPN2 and ESPN Deportes.