DeMarco was emotional in the moments after his stunning 44-second technical knockout victory over John Molina on September 8 at Oracle Arena in Oakland.
The money DeMarco earned from successfully defending his WBC lightweight title would allow him to purchase a new home for his wife and young daughter, Camilla.
He fought back tears at the postfight news conference, trying to express his gratitude for the success he'd had in his career.
He was telling yet another rags-to-riches story, but DeMarco's journey to the title was vastly different from most.
DeMarco was a teenager when he moved to Tijuana, Mexico, to pursue a professional boxing career. But he had no money and was homeless. At night, he'd climb into dumpsters and root through trash cans to find scraps of half-eaten food to give himself sustenance.
As he was fighting back tears, Seymour Zivick of DeMarco's promotional team, Gary Shaw Productions, approached the dais and informed DeMarco that he'd soon become a father for the second time. His wife stood in the back of the crowded news conference and waved at him.
DeMarco buried his face in his hands and wept.
He'll face the unbeaten Broner on Saturday in the main event of an HBO-televised card from Boardwalk Hall in Atlantic City. While Broner talks of becoming "the best ever to lace up a pair of boxing gloves," DeMarco knows full well what it means to go from the bottom to the top.
"I only dreamed that I would be a world champion some day," DeMarco said.
He'll have his hands full if he is to remain a champion. For all his bluster and bravado, Broner is an extraordinarily gifted fighter who is fast rocketing to stardom. His promoter, Golden Boy Promotions, has greased the skids for him and has matched him expertly to this point. He's never faced a particularly difficult challenge and the odds have always heavily been in his corner.
Broner is 24-0 with 20 knockouts, but regardless of his low level of opposition, he has the physical gifts to become one of boxing's elite. He's already a world-class talker who would be a first-ballot Hall of Famer were fighters inducted for their ability to brag about themselves.
He'll be far faster than DeMarco, but the question is whether he'll have the staying power that DeMarco (28-2-1, 21 knockouts) has shown.
DeMarco lost to the late Edwin Valero in 2010, going nine rounds before being stopped. But Valero was 27-0 with 27 knockouts and only five men – DeMarco being one of those – lasted more than two rounds with him.
DeMarco beat Jorge Linares in one of 2011's best fights, rallying after falling way behind.
That fight is one that should concern DeMarco supporters, though, because Linares badly outboxed DeMarco and only a late, thunderous rally saved him.
But promoter Gary Shaw said that's what makes DeMarco a special athlete. He's the kind of fighter who doesn't easily back off, and if Broner isn't careful, he could find himself in a far more difficult fight than he expects.
"Antonio DeMarco is a wonderful champion," Shaw said. "I believe he is the Mexican version of Arturo Gatti, who was a fixture in Atlantic City, so I think it is fitting that he come here and defend his world title."
DeMarco was given an extraordinarily difficult test, though. Some have argued that Broner has used the gift of gab as well as some high-powered connections to get pushed to the top, but he is fast-handed, hits hard and is an accurate puncher.
Whether he's able to put it together against a resilient fighter is another question, but Broner has no doubt that he can, and will.
"DeMarco has fought good guys, but he hasn't fought me," Broner said. "You are going to see a totally different Adrien Broner on Saturday night. I am going to be able to show more of my skills on Saturday night because DeMarco has such talent. They say if one good talent goes up against another good talent, it brings out something in the elite."
The opportunity to provide for his family and to shove those dumpster-diving days into the past forever is what brings something out in DeMarco.
He's fighting for something far greater than recognition as the best man ever to lace up a pair of boxing gloves.