AP Photo | Holly Holm, pictured getting hit in a 2017 bout, faces two-division champion Amanda Nunes on Saturday.

LAS VEGAS (AP) — Holly Holm didn’t fight in a mixed martial arts cage until she was already a 29-year-old boxing champion of three weight classes. She had both a head start and a huge deficit in her quest to master a second sport in her athletic midlife.

Even eight years later, Holm is aware of the unique challenges of her chosen path. She knows she’ll probably never face a boxer as good as her in the cage, but she also knows she might never catch up to some of her younger opponents in grappling, jiu-jitsu or the myriad intricacies of the transitions between disciplines.

So instead of setting a mundane goal to be the greatest fighter in MMA history, Holm looks at her second career as a chance to do as many unique things as possible.

“I always want to do something that hasn’t been done before,” Holm said Thursday while preparing for her showdown with bantamweight champion Amanda Nunes at UFC 239 on Saturday night.

“No female in the UFC has won the belt, lost it and then come back to get it again,” she said. “That’s something I can do this week. This is something for my legacy. I want to win no matter what, but I love to have a challenge in front of me like that.”

Holm (12-4) already had one of the greatest nights in MMA history. She knows her career is likely to be defined by her world-shocking victory over Ronda Rousey in November 2015.