The other way stood a very slim chance of working out for Mikaela Mayer.

A desire to fully conquer the junior lightweight division was always a goal, though there was growing concern that she was being frozen out by the competition. Mayer long called for unification bouts with WBA titlist Hyun Mi Choi and the WBC champ, first Terri Harper and then Alycia Baumgardner.

There was a point when it appeared that Baumgardner and Choi were on a collision course, at which point Mayer drew a firm line in the sand for when she could face either. There remains an expiration date in place for her time at 130, though it now comes with the benefit of a blockbuster showdown with Baumgarder (12-1, 7KOs) for the unified WBC/IBF/WBO and lineal junior lightweight championship.

“I was gonna give Baumgardner this year to make this fight happen with me, because I’m going up,” Mayer told, standing firm on her claim earlier this April of this being her last year at 130. The same thing with Choi. After I run through Baumgardner, I’m gonna give Choi a certain amount of time to accept this fight. I’m going up to 135 no later than February 2023.”

As previously announced, Mayer (17-0, 5KOs) and Baumgardner will collide September 10 at The O2 In London. reported news of the unification bout back in May, at a time when a Baumgardner-Choi bout was next in queue.

Having walked down that same path with the unbeaten Choi (19-0-1, 5KOs), Mayer sensed that the fight she wanted—a showdown with Baumgardner, with whom she’s rapidly developed a bitter rivalry—would work its way back around.

“I always knew this fight was going to be with Top Rank and ESPN,” insisted Mayer, a 2016 U.S. Olympian from Los Angeles who is now based in Colorado Springs. “Top Rank’s invested five years in me. Baumgardner just showed up. Matchroom just got her. There was no way they were gonna give this fight away to her.

“I’m the A-side of this fight. I’ve always said that and look where we are. Mayer versus Baumgardner and on my network. I started getting excited about when Carl and I had that discussion and here we are.”

Mayer and Baumgardner have posted wins one week apart in each of their last two starts. Mayer outlasted France’s Maiva Hamadouche to defend her WBO title and win the IBF strap in their sensational ten-round unification clash last November 5 in Las Vegas. Baumgardner crashed the title scene just eight days later, scoring a one-punch, fourth-round knockout of unbeaten WBC/IBO titlist Terri Harper to win the crown last November 13 in Sheffield, England.

Both also won shutout wins this past April. Mayer effortlessly turned away former featherweight titlist Jennifer Han on April 9 in Costa Mesa, California, the first main event in her childhood home state. One week later, Baumgardner—who lives and trains in the greater Detroit area—outclassed Argentina’s Edith Soledad Matthysse on an April 16 DAZN show from AO Arena in Manchester, England.

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 Twitter: @JakeNDaBox