Former UFC champion Anthony Pettis acknowledged on Monday that it took "a couple years" to get over his unanimous decision loss to Rafael dos Anjos in 2015 when he gave up the lightweight belt. He mentally surrendered the confidence that had made him the division's top fighter, and it played out in the coming bouts.

"RDA was the better man that night. I finally admitted it to myself," Pettis told ESPN on Ariel Helwani's MMA Show. "I was on top of the world and then that happens to you. I've never even been hit in any of my fights, basically. Then the RDA fight happens and you have to readjust.

"It's a mental block. You know what happened and want to get past it, but you also know how good you are and it's a battle in your own head that you had to figure out."

Pettis (21-7) ended up losing the next two fights, against Eddie Alvarez and Edson Barboza, respectively, and changed divisions in hopes of turning things around. He defeated Charles Oliveira by third-round submission to win his featherweight debut. He then lost to Max Holloway, returned to lightweight and is 2-1 since. Pettis impressed in July at UFC 226 by submitting Michael Chiesa by triangle armbar in the second round, earning a Performance of the Night bonus.

He describes that latest showing as "just a glimpse of where I can be at."

"Now I'm fearless again," Pettis says. "I'm going to win every sparring match. I'm going to win every session I'm in. I have God-given skills and I need to use them to the best of my ability. I thought my last fight was a great performance, but I still saw some things in my game that can get better."

Anthony Pettis defeated Michael Chiesa by triangle armbar in July. Josh Hedges/Zuffa LLC/Getty Images

Pettis has a chance to prove that again on Oct. 6 at UFC 229 in Las Vegas when he takes on top lightweight contender Tony Ferguson. The former interim champion has won 10 consecutive fights, most recently a submission win against Kevin Lee last October, but has battled injuries over the past year.

"I love it," Pettis says of the matchup. "I think he has a great fighting style. He's one of the guys who comes and brings it. I'm excited to get in there with a guy like that. He's going to try to finish the fight, and that's what I'm trying to do the whole time."