Floyd Mayweather claimed Zab Judah’s title belt-for now-with a unanimous 12-round decision, becoming a champion in his fourth weight class.

Yet, the match was defined by the fight within the fight-a 10th-round scuffle between trainers and support staff from both camps after Judah sucker-punched his unbeaten opponent.

Despite an injured right hand, Mayweather was well on his way to a win on before Judah sent him to the canvas in pain with a left hook to his groin and a right to the back of his head. "Floyd was choking me," Judah said. "I was aiming for the body. I didn’t plan to hit Floyd low."

Order was restored by quick-thinking police officers and security guards, who prevented additional amateur fighters from jumping into the ring. "Don’t you come up here!" one officer warned two members of Judah’s entourage, with his hand near his gun.

Judah (34-4) was more active and inspired at the opening bell, and the crowd began to chant his name in the second round shortly after Mayweather slipped while throwing a punch and Judah landed a right. The champion also yapped at Mayweather while the fighters stalked each other, showing his trademark bravado even against the world’s best.

But Mayweather rallied after the first four rounds with several combinations that put Judah on the defensive, then systematically employed head-bound combinations and straight rights to the body.

"He comes on strong in the first six rounds, and then he gasses out," Mayweather said. "We knew he would come out strong. That was our game plan: To relax, take our time. If there wasn’t the controversy, the fight would have ended."

Blood was evident on Judah’s face by the ninth round before the former champ turned to some questionable tactics in the 10th. Judah first nailed Mayweather with a vicious low blow and followed it up with a punch behind the head.

"I’m not a dirty fighter, I don’t use any dirty tactics," Judah said. "I was aiming for the body. I didn’t do it on purpose."

Referee Richard Steele separated the two fighters as Mayweather staggered away, only to have his uncle and trainer Roger Mayweather take umbrage with the shot and storm into the ring to chase Judah.

Mayweather was intercepted, but Judah’s corner also rushed in, setting off a wild melee that required security officials to break up. Judah was seen throwing a punch at one of Mayweather’s corner men during the fracas. Mayweather felt temporarily slowed by the incident.

"Before the confrontation, I was in my zone," Mayweather said. "Once the confrontation started in the ring, I was taken out of my zone."