By Edward Chaykovsky

Former IBF/WBC welterweight champion Andre Berto (30-3, 23KOs) is not coming for a payday. The Olympian is confident of overcoming the heavy odds to hand pound-for-pound king Floyd “Money” Mayweather (48-0, 26 KOs) the first professional defeat of his career on September 12 at the MGM Grand Garden Arena in Las Vegas, live on SHOWTIME PPV (8 p.m. ET/5 p.m. PT).

Mayweather's WBC/WBA welterweight titles will be at stake in the contest.

Berto was twice in position to fight Mayweather. The first time around, he was beaten by Victor Ortiz in a Fight of The Year brawl in 2011. Ortiz would go on to face Mayweather later that year. In 2012 he was once again in line for the fight, and once again he was beaten in a very exciting fight - this time with Robert Guerrero - who went forward to face Mayweather the following year.

The last time Berto was in the ring was on March 13th, when he stopped Josesito Lopez in six rounds. Berto is 3-3 in his last six fights.

Trained by Virgil Hunter in the Bay Area, Berto is predicting a knockout of Mayweather.

“I'm coming to kick Floyd’s ass on September 12," said Berto. "Best believe that I plan to bring it to Floyd  and I'm not concerned about what 48 other fighters have been unable to do. Somebody is getting knocked out and it won't be me. You don't want to miss this."