A three-division champion in women's boxing, Shields is seen by many as the best pound-for-pound fighter in the sport. The 26-year-old now sets her sights on a different combat discipline, as she's set to make her MMA debut on Thursday against Brittney Elkin as the main event of PFL 4.

And while it wouldn't surprise if Shields comes out on top Thursday, Mora isn't convinced she has what it takes to conquer MMA in the same manner she's done with boxing.

"Listen, I think the world of Clarissa Shields and you know, I think she's great at what she does in boxing but this isn't football or baseball," Mora said on the DAZN Boxing Show. "You can't be Bo Jackson and Deion Sanders going back and forth thinking you're going to have success. It sounds great as far as marketability goes maybe up your stock, but you can get hurt."

Mora pointed to the mixed history of boxers stepping into the MMA world as a reason to doubt Shields' latest endeavour.

"I mean, we've already seen boxers attempt to do that before," he said. "Heather Hardy is a great example of that. She's already gotten knocked out twice in four fights. Amanda Serrano already got one draw in two fights, and Holly Holm — OK, you can point at her, but she had that Buster Douglas moment with Ronda Rousey, but then she came up short with Amanda Nunes and others. So I just think this is gonna be very difficult for her to transition into because it's just a different art. It's a different science.

"They've been doing this discipline of being able to stand up and go down and everything in between. Claressa Shields has just done one discipline, and that's a 'one, two,' and that's with everything with your punches. I don't think it's gonna work. She might have success in one, two, three fights. After that, she's running into trouble."