The UFC 316 co-main event brings the long-awaited grudge match between 135-pound champ Julianna Pena and Kayla Harrison. Their bad blood didn’t start overnight. Back at UFC 307, ‘The Venezuelan Vixen’ stormed back into the spotlight with a big win over Raquel Pennington. On the same night, Harrison picked up her second UFC victory by beating Ketlen Vieira. But when it came time to call someone out, the new champ skipped right past Harrison and went after Amanda Nunes instead.

Now, we’re finally on the verge of getting answers from this long-brewing matchup. The trash talk took center stage at the press conference, and both fighters made it clear that they plan to back up every word inside the Octagon. But before fists fly and the cage door shuts, it’s worth breaking down how these two stack up—physically and stylistically. Who holds the edge? Who’s better built for this war? Time to break it all down.

UFC 316: Julianna Peña vs. Kayla Harrison stats & walkaround weight

Julianna Peñastands 5’5” tall with a 69-inch reach and hits the bantamweight limit right on the nose at 135 pounds. Across from her, Kayla Harrison comes in a bit taller at 5’8”, but surprisingly, her reach is shorter—just 66 inches. That gives the champ a noticeable edge when it comes to striking at range. And in a fight where every inch matters, those extra few could be a game-changer. 

Since it’s a title fight, both women have to hit that 135-pound mark. For Kayla Harrison, that’s a big cut—she’s known to walk around at 165, so dropping that much weight is no joke. On the flip side, Julianna Peña has never shared her walk-around weight, but she’s never missed weight either and always shows up looking fight-ready.

The real question is: how big will the size difference actually be once they step into the Octagon? Harrison clearly has more muscle on her frame, but when she faced Ketlen Vieira, the size gap wasn’t all that obvious. So while she might have a slight physical edge, it probably won’t be a major factor, at least not on the surface.

Julianna Pena lands 3.25 significant strikes per minute with a 60.69% accuracy rate and absorbs 2.53 strikes, giving her a striking defense of 57%. Though based on a small two-fight sample, Harrison has shown impressive efficiency, landing 4.87 strikes per minute at 64% accuracy.

On the ground, the 135-pound champ pulls off about 1.8 takedowns per fight, landing just over half of her shots at 56%. Her takedown defense, though, is pretty low at 23%. She also throws in around 0.8 submission attempts each fight. Harrison, on the other hand, averages nearly three takedowns per fight but lands them about 30% of the time. 

What stands out is her perfect takedown defense—she hasn’t been taken down in the UFC  yet. And she averages about 0.7 submission attempts per fight. With the numbers in place, let’s look at how they might actually play out inside the cage.

Pena vs. Harrison breakdown and prediction

The fight between Julianna Pena and Kayla Harrison is a fascinating clash. Both bring very different skill sets to the table, which makes the matchup even more intriguing. So far, the challenger has grabbed plenty of support from the MMA world. The Olympian Judoka is favored at -800, while the champ comes in as a +550 underdog. But is that really how it’ll play out? Let’s break it down.

At this point, ‘The Venezuelan Vixen’ heads into her title defense with many doubting she can stand up to her opponent. But it’s important to remember that, while Pena might be less technical, she’s always hunting for openings—and knows how to capitalize on them. Just look at her first fight with Amanda Nunes, and even the second one, where she nearly locked in some armbars. The 135 lbs champ also knows how to mix in takedowns, like she did against Raquel Pennington, which ended up making all the difference in that fight.

On the flip side, Kayla Harrison has the tools to dominate with her hip throws and footwork, setting herself up for an overwhelming victory. She’s already proven her striking skills, showing she can handle the stand-up game as well. But her biggest edge will likely come from her takedown defense—keeping the fight where she wants it—and then gaining top control to rain down ground-and-pound shots.

For Pena, a key to victory will be using plenty of feints to throw off Harrison’s timing, then hitting hard with uppercuts. She should consider setting up a head kick—just like Holly Holm used to famously stop Ronda Rousey—especially when Harrison pressures forward with her hands low. As for Harrison, she should focus on working her straights and hooks, which tend to land well against Pena. Using clinches to set up sweeps and takedowns will also be crucial for controlling the fight on her terms.

In terms of prediction, Kayla Harrison has everything it takes to become the new champion. Although there’s always a threat from a fighter like Julianna Peña, the former PFL champ is poised to claim the UFC title as well. That being said, who are you picking to win the UFC 316 co-main event?