Reina Tellez’s boxing journey will soon come full circle.

Tellez first took up the sport in 2011, while Amanda Serrano won her first world title the same year with a second-round stoppage win over Kimberly Connor-Hamby. Now, the undefeated prospect will stand across from the seven-division champion in Serrano’s return home to Puerto Rico.

The 22-year-old from San Antonio, Texas, will make a massive step up in competition when she faces Serrano for her WBA, WBO and The Ring featherweight titles on Saturday at Coliseo Roberto Clemente in San Juan, Puerto Rico, on DAZN. The title bout will be contested across 10 three-minute rounds.

“I'm extremely grateful to even be on this platform, but let alone fight somebody I watched growing up in my career,” Tellez said at the final press conference Tuesday. "It's just crazy to say. I just think about it, and I can't fully process it because it's real. I didn't think I was going to be in this position, let alone this year.”

Serrano (47-4-1, 31 KOs) was originally set to face Erika Cruz, but an atypical finding in a Voluntary Anti-Doping drug test led to her being replaced by Tellez on Dec. 18. For Tellez, it didn’t take much thought on whether she’d step up to face Serrano on late notice.

“It took me about a day,” Tellez said. “This is a once-in-a-lifetime opportunity, and you just never know when it's going to come back around. I have nothing to lose. It's everything to gain. It's a high-risk, high-reward type of situation, and I'm grateful for it.”

Serrano, 37, expressed gratitude toward Tellez for taking the fight on just over three weeks' notice.

“Thank you so much, truly from the bottom of my heart, for stepping up, which shows that you are a true warrior,” Serrano said. “Only the best people who dare to lose, they're gaining so much more respect. I'm excited to share that ring with you. I know you’re going to come with everything because you want to prove to the world that you want the people to remember your name.”

Tellez (13-0-1, 5 KOs) last fought on Sept. 19, when she won every round on the three judges’ scorecards in a unanimous decision victory over Mayela Perez (20-31-4, 10 KOs). Tellez will be in her first 10-round fight and compete in three-minute rounds for the first time.

Despite the uphill climb she faces, Tellez would be much more at peace seeing things through rather than wondering what could have been. And while there was mutual respect and adoration shared between the two, Tellez believes she’ll have no problem putting that aside once she steps inside the ring.

“She bleeds how I bleed,” Tellez said. “Everybody does. I give her the utmost respect, but at the same time, it's a fight. I'm not going to let that get in the way.”