By Keith Idec

One of Floyd Mayweather Jr.’s greatest strengths throughout his ascent to superstardom has been an ability to remain focused on training.

Mayweather never overlooks opponents and he isn’t about to start with Andre Berto. The undefeated five-division champion is an enormous favorite over Berto, but the 38-year-old Mayweather claimed on a conference call Wednesday he has trained even harder for his WBA/WBC welterweight title fight against Berto than he did for his incomparably hyped showdown with Manny Pacquiao four months ago.

The Grand Rapids, Michigan, native views Berto as a dangerous opponent, no matter how much of a mismatch media members and fans consider a fight Mayweather insists will be the last of his 18-year, Hall-of-Fame career.

“He feels like he has nothing to lose,” Mayweather said. “And I think that when you have a guy that’s put in a situation with nothing to lose, it makes him work that much harder. He has a chance to be one of the top guys in the sport when I’m through. So is he trying to dethrone Floyd Mayweather? Absolutely. Anything is possible. Like they say in football, any given Sunday, I’ll say any given Saturday. Anything can happen. So I’m prepared mentally and physically. I’m ready. I’m sure he’s in top shape and he’s ready. But I’m not going to overlook this guy.”

Mayweather (48-0, 26 KOs) and Berto (30-3, 23 KOs), of Winter Haven, Florida, will headline a four-fight Showtime Pay-Per-View card Sept. 12 at MGM Grand in Las Vegas (8 p.m. ET/5 p.m. PT; $74.95 in HD).

Keith Idec covers boxing for The Record and Herald News, of Woodland Park, N.J., and BoxingScene.com. He can be reached on Twitter @Idecboxing.