LAS VEGAS – As someone who once competed at a higher weight class but now quite enjoys her new home, Jessica Eye has some concerns for anyone going the other way.

“I am jacked about how much I know my size will play into a factor with this,” Eye told MMA Junkie. “I remember going up a weight class and thinking that, ‘Oh, I can hang with them.’ You know what I mean? ‘It’s hard to make flyweight, but I can hang with bantamweights’ – and that’s not true. That wasn’t true. It really wasn’t.”

Recent UFC women’s flyweight title challenger Eye (15-7 MMA, 5-6 UFC) takes on Cynthia Calvillo (8-1-1 MMA, 5-1-1 UFC) in the main event of Saturday’s UFC on ESPN 10 event from UFC Apex. The card airs on ESPN and streams on ESPN+.

Calvillo is moving up a division after twice missing weight in her seven UFC strawweight appearances, and she gets a big fight in her debut at flyweight facing Eye, who is ranked No. 3 in the latest USA TODAY Sports/MMA Junkie MMA rankings. However, Eye said she had no hesitation in taking a contender who is unproven at 125 pounds, accepting UFC matchmaker Mick Maynard’s offer immediately – or, at least, immediately after he finally tracked her down with the help of Xtreme Couture’s Eric Nicksick.

“I was taking a nap that day from my earlier training, and when Mick called me, I didn’t see it,” Eye said. “Then Eric blew my phone up. As soon as I finally picked up the phone, he was like, ‘Jessica, you vs. Cynthia Calvillo, main event if Dana (White) approves it on June 13 here in Vegas.’ I was like, ‘In Vegas? Well, yeah, but let me wake up. Hold on.’

“I literally walked to my living room where my friends were at, and I was like, ‘They just offered me a main event fight June 13. I’m going to take it.’ They were like, ‘F-ck, yeah. Let’s do this.’ So was my team.”

Eye certainly isn’t looking at the matchup as some type of walkover. After all, even though she feels Calvillo may be in for a rude awakening, she certainly doesn’t see her as incapable. And with a shot at make an immediate impact in the division on the line, Calvillo is bound to be driven.

“I know Cynthia is a gamer,” Eye said. “I’m sure this has got to heighten her sense. I’m sure she’s bringing her A game. She’s fighting the No. 1 girl. This could be a big jump for her. This could be a big day for her, you know what I mean?

“I could see why she would want the fight, and you know why I want the fight? Because I want to prove that no matter who they put in front of me, I am as good as I believe I am and as good as I know I am, and I like winning. I like winning, and it’s all about a win.”

Eye vs. Calvillo has taken a bit of criticism from fans for its placement as a headlining bout, but the 33-year-old Ohio native said she isn’t worried about those opinions. Instead, it’s all about building off her December win and proving that her 4-1 record in the UFC since moving down from 135 pounds is no accident, and she still belongs at the top of the division.

And unfortunately for Calvillo, Eye says, that could mean a very rude welcome to her new neighborhood.

“I guess we’ll have to see whether or not I lace that right hand straight down the pipe or I put it on her body and break her body down to where she can’t stand,” Eye said.