Jeff WagenheimJun 4, 2025, 10:00 AM ET
Julianna Peña is in her second reign as UFC women's bantamweight champion. In winning three of her past four fights, she has beaten two other champs. That's the kind of résumé that should situate a fighter on top of the world. And yet the MMA world continues to discount Peña.
She defends her belt Saturday at UFC 316 in Newark, New Jersey (ESPN+ PPV, 10 p.m. ET), and despite her opponent, Kayla Harrison, being a relative newcomer who has been barely tested at the sport's highest level, Peña will be the one going into the fight as a sizable betting underdog.
So what else is new?
For Peña, being overlooked is her life story. Growing up in Spokane, Washington, as the youngest of four children, she was a regular target of her older brother's roughhousing. "He was a gigantic WWE fan, and he beat the snot out of me and my two older sisters," Peña told ESPN, adding with a smile, "I was his favorite, because I would never cry, and, even though he was so much bigger and stronger than me, I kept attacking him with everything I had."
Persevering through battle royals with an Andre the Giant wannabe fell right in line with her upbringing by a mother determined to instill toughness in her youngest.
"She used to tell me, 'You will stand up for yourself,'" Peña recalled. "My mom put that spirit inside of me, of never backing down."
This will be Peña's fourth consecutive fight as an underdog. Most famously, she overcame the fourth-longest odds in UFC title fight history to submit Amanda Nunes. She lost the 2022 rematch seven months later, but last October she recaptured the title by dethroning Raquel Pennington, who was favored in their fight by nearly 2-to-1 odds.
How long has it been since Peña walked into the cage as a favorite? It last happened way back in 2021, when she defeated Sara McMann at UFC 257. The headliner that night was a long-inactive fellow by the name of Conor McGregor. Remember him?
Peña had to overcome obstacles on her way to the big show. She was on a two-fight losing streak on the regional scene in 2013 when she was cast on Season 18 of the UFC's reality TV show, "The Ultimate Fighter," yet she won the show and a UFC contract under the coaching of her friend and training partner Miesha Tate. The opposing team's coach was Tate's bitter rival, dominant champ Ronda Rousey, and the heat between them spilled over to the fighters. That animosity drew Peña all the way to Australia a couple years later to root against "Rowdy Ronda" in a title fight with Holly Holm that was widely expected to be a mismatch. "I was front row, cheering Holly on, giving her all my energy," Peña recalled. "When they entered the Octagon, I remember [Holm] pacing back and forth in her corner. And I stood up at my seat and was pointing to her, yelling, 'You got this! You can do this!'"
As it turned out, of course, Holm could do it. As an unimaginable +870 underdog, she picked apart, frustrated and bloodied Rousey on the way to a vicious second-round knockout.
"I was beyond ecstatic to see Holly do that. It was so inspiring to see," Peña said. "The things I took away from that fight were that the whole world can count you out, but as long as you have belief in yourself, you're capable of anything. And that nobody is invincible."
Both takeaways came in handy for Peña years later when she was preparing to challenge Nunes. The moment her rear-naked choke vanquished the champ, the stunned crowd went eerily quiet, and Peña learned something else about herself.
"I find the sound of silence beautiful," she said. "When you're an underdog, it's just an opportunity to silence everybody who doubted you. There's nothing better." When Peña steps into the cage with Harrison this weekend, she will be seeking to silence her doubters once more. As of Wednesday, Peña is a +500 underdog, per ESPN BET. Can she top any of the notable UFC shockers of the past? Here's one observer's ranking of the most impactful title fight upsets.
The closing odds listed below were sourced from ESPN's UFC database.
1:22
Valentina Shevchenko wins back women's UFC flyweight title at UFC 306
Valentina Shevchenko defeats Alexa Grasso in the co-main event of UFC 306 to gain back her women's UFC flyweight title.
10. Alexa Grasso (+600) defeats Valentina Shevchenko by fourth-round submission
UFC 285, March 4, 2023
During her four years as women's flyweight champion and even before, Shevchenko had given fans reason to believe she was invincible in fights against mere mortals. The only two losses in her 14-fight UFC career to that point had come against Nunes, and they'd happened up in the GOAT's 135-pound weight class, not down in Shevchenko's 125-pound class. Among Shevchenko's most fight-deciding weapons had always been her kicks, and on this night she unleashed one that essentially ended the bout -- and her title reign. Late in Round 4 of a fight she was winning on the scorecards, Shevchenko spun for a body kick but it missed, leaving her back exposed. Grasso grabbed hold and quickly secured a rear-naked choke to pull off the upset.
9. Amanda Nunes (+220) defeats Cris Cyborg by first-round knockout
UFC 232, Dec. 29, 2018
Cyborg was no stranger to quick finishes. To this point in her career, half of her victories had ended in Round 1. She was a one-woman wrecking crew. But on this night, she was the one getting wrecked ... and quickly. The two champions -- Cyborg at featherweight, Nunes at bantamweight -- both came out swinging, and the faster Nunes repeatedly beat her bigger opponent to the punch. One knockdown. Two. Three. Four. It was over in 51 seconds, making Nunes one of just four UFC fighters to be a champ in two divisions simultaneously.
1:14
Flashback: Michael Bisping wins middleweight gold with KO of Luke Rockhold
Turn back the clock to UFC 199 when Michael Bisping shocked the MMA world and beat Luke Rockhold in Round 1 to win UFC gold.
8. Michael Bisping (+400) defeats Luke Rockhold by first-round KO
UFC 199, June 4, 2016 (watch the fight on ESPN+)
Just 18 months before this fight, Rockhold had indignantly finished Bisping with a guillotine choke -- using just one arm. No one was begging to see more of that, but there the UFC was, 10 days before a pay-per-view main event and in need of a replacement opponent for then-UFC middleweight champion Rockhold after former champion Chris Weidman was forced out because of injury. The call went out to Bisping. Did Rockhold take him lightly in the rematch? The champ held his hands defiantly low and looked lethargic from start to finish. And what a brutal finish it was, with Bisping clipping his bitter rival with a left hook and gleefully finishing him on the canvas.
7. Frankie Edgar (+620) defeats BJ Penn by unanimous decision
UFC 112, April 10, 2010
There was a time when Penn was widely considered the gold standard of MMA. A two-division UFC champion, he had made a career of fighting bigger men, including champions Georges St-Pierre, Matt Hughes and Lyoto Machida. Edgar, on the other hand, lacked that golden pedigree and was small for a lightweight, but he established himself as the little engine that could against Penn. He outworked "The Prodigy" on his way to a unanimous decision, although the fight was so close that the UFC booked a rematch four months later. Edgar won that one, too, later writing for ESPN, "Going into the first fight, I believed I could beat BJ. I didn't know, but I believed. Going into the second fight, I knew I could. I think that's why the gap between us was a lot bigger the second time."
6. Henry Cejudo (+400) defeats Demetrious Johnson by split decision
UFC 227, Aug. 4, 2018 (watch the fight on ESPN+)
"Mighty Mouse" had won 13 fights in a row, including a record 11 defenses of the men's flyweight title, going into his rematch with Cejudo, whom he knocked out in the first round two years earlier. So this turnaround was a shocker. It might have appeared higher in these rankings if the fight hadn't been scored a split decision that many observers thought should have gone Johnson's way. Instead, the win set Cejudo on a path toward glory, as in the rare and coveted champ-champ status.
5. Julianna Peña (+650) defeats Amanda Nunes by second-round submission
UFC 269, Dec. 11, 2021
Yes, "The Venezuelan Vixen" deserves a spot among the top five of title fight upsets. She beat the GOAT at a time when Nunes was champion of two weight classes and had won 12 fights in a row. Peña entered the fight just 10-4 as a pro and 2-2 in her most recent four bouts. Where was her path to victory? No one could find one -- except Peña herself. "I have a supreme belief in myself, because I know how much passion and dedication I have for this sport," she said. "Me beating Amanda that night just came down to pure belief and hard work."
4. Chris Weidman (+200) defeats Anderson Silva by second-round KO
UFC 162, July 6, 2013 (watch the fight on ESPN+)
Silva had owned the middleweight championship for seven years -- a UFC-record reign of 2,457 days. Along with making 10 title defenses, he had even taken several bouts at light heavyweight, extending his winning streak to 16 in a row, the most consecutive victories in UFC history. "The Spider" was not simply beating everyone, he was making them look like fools. Silva toyed with Weidman, too, early in this fight. But the challenger was undeterred. He kept moving forward, even as Silva evaded everything he threw. When Weidman missed with a right hand early in the second round and swiped his fist back toward the champ's head, it threw off Silva's timing for a split second -- just long enough for a follow-up left hand to drop Silva and send shockwaves through the sport.
3. Matt Serra (+850) defeats Georges St-Pierre by first-round TKO
UFC 69, April 7, 2007
This one is often cited as the biggest title fight upset in UFC history. That makes sense on the face of it -- GSP, a leading candidate for GOAT status, losing to a reality TV show contestant. But Serra's season of "The Ultimate Fighter" featured a cast of fighters with UFC experience. Serra had made nine previous Octagon appearances, including going the distance against Penn, a former champion. And St-Pierre, making his first defense of the welterweight title, had not yet established his supremacy. Having said all that, this still was a shocking result, especially considering how easily St-Pierre had handled Hughes to win the title five months earlier. Going into the fight with Serra, it appeared that a new era was dawning. Then, a looping right hand by Serra sent the champ crumbling, along with any expectations.
2:44
McGregor: 'I did say the right hand would be his downfall'
UFC featherweight champion Conor McGregor joins SportsCenter to break down his 13-second knockout win over Jose Aldo at UFC 194 and if he'd be willing to give Aldo a rematch.
2. Conor McGregor (+100) defeats. José Aldo by first-round KO
UFC 194, Dec. 12, 2015 (watch the fight on ESPN+)
Numerically, this one doesn't measure up to the other presumed mismatches on this list, but canonically it represented a major turning point in the sport's trajectory. McGregor actually opened as a slight favorite at some sportsbooks. Oddsmakers clearly were swayed by the celebrity popularity of McGregor and their understanding that some devotees would lay down money on the Irishman despite him never having been in the cage with anyone even close in stature to Aldo, winner of 18 in a row. McGregor talked a good game, and that was enough for some.
The record shows that McGregor beat Aldo in 13 seconds. But he actually won the fight well before that. McGregor taunted the champ even before they were booked to fight, and the mind games only ramped up as the fight got closer. During a prefight news conference, McGregor grabbed the belt from the dais and held it high, as if it were his. By fight night, Aldo was livid. He came out of his corner with uncharacteristic aggression, and in the very first exchange, McGregor cracked the champ with a counterpunch that sent Aldo crashing to the canvas and McGregor's star power skyrocketing. That punch, and what led to it, changed MMA forever.
1:11
Holm's KO of Rousey shocked the world
Holly Holm shocked the world by knocking out Ronda Rousey at UFC 193 in front of over 56,000 people in Melbourne. Order UFC 243 here https://plus.espn.com/ufc/ppv.
1. Holly Holm (+870) defeats Ronda Rousey by second-round KO
UFC 193, Nov. 14, 2015 (watch the fight on ESPN+)
This was the upset to upstage all upsets, although MMA fans of recent vintage might not view it as such an enormous shocker. Looking back now, a decade later, one might remember Rousey for getting smashed in her final two fights before slinking off into retirement. But prior to that, she was the sport's most dominant fighter -- by far. "Rowdy Ronda" entered the Holm fight at 12-0 with 12 finishes, all but one of them coming in the first round. Rousey's three fights previous to the Holm bout had ended in 16, 14 and 34 seconds. No one could hang with her.
Then, before a crowd of 56,214 at an Australian rules football stadium in Melbourne, Rousey ran into Holm. She mostly ran into Holm's left fist, again and again. It was stunning to watch the fight not immediately go to the mat, like all previous Rousey fights had. It was stunning to see the champion's face redden and her spirit dissipate. It was stunning to see Holm's head kick in the opening minute of Round 2 send Rousey and her aura of invincibility crashing to the canvas.
