Broner put on a scintillating display against established Mexican WBC lightweight champion DeMarco at Boardwalk Hall to send him to the canvas and become a two-weight world champion.
"I was shakin' and bakin' him until I flipped him up," said Broner, who remained unbeaten. "I knew coming in it was going to be a world class fight. But I knew he didn't have the skills to beat me. I wanted to make a statement and I did."
And Broner, a 23-year-old Cincinnati native, was shakin’ and bakin’ from the outset, releasing a flurry of hard shots to the head that a submissive DeMarco tried to defend but leaving his head wide open to the onslaught.
The fight stayed one-sided throughout the first seven rounds, with DeMarco taking bruises under both eyes in a cringeworthy carve-up that saw the Mexican grow ever-wearier.
Broner undid DeMarco in the eighth round, with one left uppercut that slammed so hard into his opponent’s jaw he was forced to one knee, and the referee stopped the fight at 1 minute 49 seconds of the round.
"His defense and shoulder roll was hard to penetrate," said DeMarco of the contest. "I fought my heart out and I'll be back."
Broner landed 241 of 451 total punches (53 per cent), while DeMarco landed 93 of 351 (26 per cent).
DeMarco's promoter, Gary Shaw, was impressed with Broner, labelling him as “the next Floyd Mayweather”.
"I think he's the total package. He's special."
In the co-feature Detroit heavyweight Johnathon Banks stopped Seth Mitchell in the second round.
Banks used a barrage of nifty combinations to send the former Michigan State linebacker down three times in the second, triggering the referee to stop the fight at 2 minutes 38 seconds.