Claressa Shields, just 4½ years and 11 fights into her professional boxing career, already has significant achievements in the sport.

The undefeated two-time U.S. Olympic gold medalist became the undisputed women’s junior middleweight world champion on March 5 via shutout decision over Marie-Eve Dicaire, adding yet another significant line to a resume that also includes having been the undisputed middleweight champion and a unified super middleweight world titlist.

Now, Shields, who holds The Ring women’s titles at middleweight and super middleweight and ranks No. 2 on the pound-for-pound list, is preparing for her debut in MMA with a goal to win a world title and become the first fighter — male or female — to simultaneously hold titles in MMA and boxing.

Shields announced in December that she was going to participate in both sports and now her MMA debut is here. She signed with the Professional Fighters League and is set to face Brazilian jiu-jitsu specialist Brittney Elkin in the lightweight (155 pounds) main event of the kickoff of the second half of the PFL regular season on Thursday (ESPN2, 10 p.m. ET) inside the bubble of the Ocean Casino Resort in Atlantic City, New Jersey.

Her reason for seeking to compete in both sports besides the financial rewards is simply because she wants a challenge.

“I feel like my legacy in boxing can never be tarnished. I’ve accomplished too much,” Shields said Monday on a media video conference she and Elkin participated in to discuss the fight. “So, I really wanted to try MMA. A couple of years ago I was thinking about the transition but I never really wanted to go into MMA. When the opportunity presented itself with the PFL it was a great conversation with the owners.

“I had a conversation with God, I had a conversation with my family and myself knowing making the transition wasn’t going to be easy. Boxing has always come easy to me. I was a complete fighter before I was 14, 13 years old. Now, I’m going to MMA and starting from the bottom and I was asking myself, ‘Are you prepared to start from the bottom and work your way up?’ And the answer I gave myself was, ‘Hell, yeah!’ It was time to try something new.”

Doing what she does best, Shields nails Marie Eve-Dicaire. Photo by Carlos Osorio/ Associated Press

Shields, 26, of Flint, Michigan, has spent the better part of the past seven months training at the famed Jackson Wink MMA Academy in Albuquerque, New Mexico, where she trained with — and absorbed considerable knowledge from — the gym’s two most famous members, UFC superstar Jon Jones and former UFC and boxing champion Holly Holm.

Shields has spent ample time learning about the various disciplines used in MMA and also had to adjust from fighting scheduled 10-round boxing matches with two-minute rounds to preparing for an MMA contest that is scheduled for three rounds with each round lasting five minutes.

“My kicking is coming along well. I feel my jiu-jitsu and even my wrestling has come along well,” Shields said. “Everything has been great. Honestly, I wouldn’t be here if I thought I was going to be in the cage at a disadvantage and lose.

“Everybody is making a big deal that Brittney Elkin is purple belt in jiu-jitsu, but MMA is not just jiu-jitsu. It’s boxing, it’s kickboxing, it’s wrestling. It’s all these different arts and I don’t think people should just count me out because I’m not a ground specialist. It’s about who can use what they know the best. I’ve practiced in all of them and I think I have a great chance to win on Thursday and have a great transition.

“I’m of course gonna let my hands go because that’s what I’m known for and that’s what I know best. But I got comfortable putting a few different (disciplines) together to make my game plan a little bit more complex. I got a few other things up my sleeve besides just boxing.”

Thinking back to her early weeks in Albuquerque, Shields said she has come a long way after a difficult adjustment to so many new ways of fighting.

“When you first start you’re laying there on your back and you’re like, ‘What am I doing?’ We use our legs but in boxing you more use your upper body, so I had to put everything together,” Shields said. “You go from boxing to wrestling to jiu-jitsu. You got to put all those mindsets together. It can be very, very challenging, especially for boxers.

“The wrestling came to me easy and then I mixed the other things in. And I had to get my mind ready to fight for five minutes (per round). That was the biggest thing at first, but after doing it for all these months, now I understand it. I get it and it makes a lot of sense to me. But at first everything besides boxing was hard.”

Shields is out to silence the doubters. Photo by Stephanie Trapp/ SHOWTIME

Other top women’s boxers have crossed over to MMA in recent years, including Amanda Serrano, a unified featherweight titleholder and winner of world titles in a women’s record seven weight classes, and former featherweight world titlist Heather Hardy. Before they did it, Holm did and achieved tremendous success. Shields said Holm has been an important part of her transition to MMA.

“I haven’t been able to pick Heather Hardy’s or Amanda Serrano’s brain but I’ve been able to pick Holly Holm’s brain and I’ve been able to pick Jonny Bones’ (Jones) brain,” Shields said. “I want to be MMA champ and boxing champ at the same time. Holly Holm did it but she did it one at a time. That’s the only difference. So, me and her had plenty of conversations and we had plenty of sparring sessions to help me prepare for this fight.”

PFL CEO Peter Murray said Elkin, who has competed in various MMA promotions, including in the PFL, is no pushover opponent for Shields to blow out in her MMA debut despite her 3-6 record.

“Claressa has made it clear that her goal is to become the first person to hold world championships in boxing and MMA and we’re proud to support that journey and provide fans with that excitement. It was clear we needed to have an opponent for Claressa that presented a major challenge in this debut and Brittney is a nine-fight veteran in MMA,” Murray said. “She’s as tough and dangerous as they come. She’s a Brazilian jiu-jitsu purple belt. She poses a serious threat to Claressa.”

Elkin, of Westminster, Colorado, said she has watched videos of many of Shields’ boxing matches to study her footwork.

“My goal is just to make her game plan not work out. It’s not shutting down some new elite athlete in the sport,” Elkin said. “The task is (to focus on) my fight. I’m gonna do my best to shut down her tools. I watched her videos a lot. I feel confident I can lead her into what I have to offer.

“I plan to face a prepared athlete for this fight. I am aware that she has (good) hands. I’m aware of a lot of things I’m prepared to do to her. I’m prepared to do ground or stand up, offense of defense.”

Elkin was surprised that she got the fight. She said the phone call from PFL matchmaker Ray Sefo offering her the fight came on April Fool’s Day and she did not believe him initially.

“At first I thought it was a joke,” Elkin said. Then she realized Sefo was serious.

“Then I started to really look at it and it’s a great matchup,” Elkin said. “I’m pretty f—– excited.”

Shields admitted that had the fight with Elkin been a few months ago she would have been nervous about it, but not anymore. She feels as though she has had plenty of time to make the necessary adjustment from boxing to MMA.

“I don’t have any nerves because nerves do not help you for the fight,” Shields said. “I feel like I prepared to be here. I would have had nerves if they would have told me this fight was happening four or five months ago. I would have been like, ‘Oh, my God,’ because I hadn’t really submerged myself in it yet.

“But now that I’ve been doing it for seven months and I’ve had so much training, so much time to learn so many different things and understand what I’m doing, understand what it is I need to do for this fight, I’m completely comfortable and I look forward to Thursday. Instead of having nerves, I’m actually excited. I’m excited to fight and excited to come out victorious.”

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