LOS ANGELES — Former four-time champion Sugar Shane Mosley intends to prove again that he's one of the best fighters around, so that means he must beat the best.

Mosley, who turns 37 on Sept. 7, faces Ricardo Mayorga on Sept. 27 but already is lobbying for a shot at WBA welterweight champion Antonio Margarito.

"I go after the best fighter. It doesn't matter who it is," Mosley said. "When Mayweather (Floyd Mayweather Jr.) was on top before he retired, I wanted Mayweather. Margarito is the best welterweight out there right now, so I want Margarito.

"I love the challenge. I've always been that way, wanted to be the best. So if he's the best fighter, I'm going after him."

The 30-year-old Margarito, who seems to have improved with age and experience, stopped Miguel Cotto on July 26 in Las Vegas to take the WBA crown.

Mosley lost a 12-round decision to Cotto last November in New York, couldn't get a rematch, then set up a bout against Zab Judah. But that was called off when Judah injured his arm.

Mosley obviously must get past Mayorga in their bout at the Home Depot Center in suburban Carson if he is to realize a goal he's set for the next few years.