LOS ANGELES — Floyd Mayweather Jr. says Andre Berto is a worthy opponent for the final fight of his perfect career.

Three months after Mayweather (48-0, 26 KOs) dominated Manny Pacquiao in the most lucrative fight in boxing history, he began the difficult business of promoting his pay-per-view bout with Berto on Thursday with a news conference in downtown Los Angeles.

Mayweather acknowledged the immediate backlash from his choice of Berto (30-3, 23 KOs), a former welterweight champion who has lost three of his last six fights. Mayweather promises an exciting fight, even guaranteeing somebody will get knocked down.

“The guys who have failed … they couldn’t keep up with (Mayweather),” Berto said. “I’ve got certain tools – speed, explosiveness – that other guys haven’t had.

“They can doubt it if they want, but I can tell you, you don’t want to miss it.”

Mayweather also repeated his declaration that this is the last fight of his career, although he grinned broadly while saying it.