Alycia Baumgardner doesn’t foresee her rivalry with Mikaela Mayer lasting beyond their upcoming fight.

What the heavy-handed junior lightweight titlist can envision, is leaving behind an everlasting impression.

The months-long feud between Baumgardner and Mayer will transform from the mean Twitter streets to the boxing ring, when the world’s top two junior lightweights collide September 10 at The O2 in London. Baumgardner (12-1, 7KOs) will put her WBC and IBO 130-pound titles on the line versus Mayer (17-0, 5KOs) who looks to defend her unified IBF/WBO crown.

The winner will emerge as the unified and lineal champion, though Baumgardner aims for a far more satisfying prize.  

“When we are both gray and old, Mayer is still going to be having Alycia Baumgardner flashbacks,” Baumgardner vowed. “When she is lying horizontally in the ring, Mayer will think back to the first time my name left her mouth and she’s going to wish it hadn’t.

“I guess we’re going to find out if Regina George has a chin. Not only will Mayer feel my power, but her descendants are also going to feel what I do to her.”

The war of words dates back to Baumgardner’s sensational one-punch, fourth-round knockout of unbeaten Terri Harper to win the WBC/IBO junior lightweight titles last November 13. Mayer—who’d just unified the IBF/WBO belts eight days prior—had already developed a rivalry with Harper, with hopes of unifying versus South Yorkshire’s first-ever female pro boxer had she beaten Baumgardner.

Mayer’s focus immediately shifted to Baumgardner—an Ohio native who now lives and trains in the greater Detroit area—after the win, with boxing’s fiercest rivalry born soon thereafter. Both have since added a successful title defense to their ledger, coming one week apart in April. From there came more trash talk between the two, all for the glory of Boxing Twitter as anticipation grew for a head-on collision.

Baumgardner initially eyed a different path to unification, with talks of a showdown versus WBA titlist Hyun-Mi Choi. Both are represented by Matchroom, who co-promotes Baumgardner along with Marshall Kauffman’s King’s Promotions. When those plans fell through, talks shifted to a mouthwatering Mayer-Baumgardner showdown, a fight that Mayer has openly campaigned for months. Baumgardner ultimately granted her wish, a decision she plans for Mayer to deeply regret.

“Not only will I take Mayer’s belts, but I’ll take everything from her,” vowed Baumgardner. “She’ll be lucky if I let her keep her name. If I’m not haunting her dreams before the fight, I will be after it.

“If you come at the queen, you best not miss. On the bright side for Mayer, a loss to me will be the best result on her resume.”

Mayer-Baumgardner serves as the co-feature to another long-awaited grudge match, as Claressa Shields (12-0, 2KOs) and Savannah Marshall (12-0, 10KOs) collide for the undisputed middleweight championship.

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox