LAS VEGAS -- A near-riot in the closing seconds of the 10th round only delayed the inevitable: A dominant Floyd Mayweather Jr. victory.
After a highly competitive first half of his fight with Zab Judah, Mayweather took over and showed why he is the world's best fighter, pound-for-pound, winning a unanimous decision in their welterweight showdown Saturday night at the Thomas & Mack Center.
The fight was called "Sworn Enemies" because of the heated relationship between the fighters, but the venom spilled over to the corners late in the 10th round.
Judah landed a bad low blow and followed with a chopping right hand behind the head, both illegal punches.
As Mayweather doubled over in pain and limped toward a neutral corner, his uncle and trainer, Roger Mayweather, entered the ring and stormed toward Judah.
Referee Richard Steele intercepted him in the middle of the ring, but by then Yoel Judah, Zab's father and trainer, had stormed the ring.
He headed straight for Roger Mayweather and threw a punch as security and spectators from the crowd of 15,170 filled the ring in a scary scene that lasted for several minutes, and left doubt as to whether the fight would continue. During the melee, Roger Mayweather tried to choke Judah.
After the ring was finally cleared, the fight resumed, and five seconds later the 10th round ended.
Roger Mayweather was no longer in his nephew's corner, having been ejected and replaced by assistant Leonard Ellerbe.
Skip Avansino, the chairman of the Nevada Athletic Commission, said the purses for both fighters -- $5 million for Mayweather and $1 million for Judah -- were being held pending a review of the fight film. In addition, Roger Mayweather was immediately suspended by the commission.
Judah promoter Don King was vocal in his call for a Mayweather disqualification because under the rules, no one besides the fighters and referee is allowed in the ring during a round.
"Once you get on the apron, the fight is a disqualification," King bellowed at ringside. "It should be total disqualification. There was a third man in the ring chasing the fighter during the round. The fight is over when the man stepped on the apron, and this man came all the way into the ring. We got to do this again."
Mayweather (36-0) cruised the final two rounds -- even embracing Judah before the 12th rather than simply touching gloves -- instead of continuing to lay punishment on him as he had been doing for the previous several rounds.
"I could have gotten him out of there, but the confrontation threw me out of my zone," Mayweather said. "Once that happened I decided to box the last two rounds and go home with the victory."
The win, on scores of 119-109, 117-111 and 116-112, netted Mayweather the tainted IBF welterweight belt.
When Judah (34-4) was the undisputed 147-pound champion, he was almost knocked out during a clear decision loss to Carlos Baldomir in January.
However, because Baldomir didn't pay a sanction fee, the IBF incredibly left Judah as the champion rather than vacating the title that now belongs to Mayweather.
ESPN.com at ringside scored it 116-112 for Mayweather.
HBO will air a replay of the fight next Saturday night at 9:30 ET/PT.
Judah, 28, had success early in the fight, and his southpaw style and quickness seemed to give Mayweather, 29, problems.
"I know Zab is a frontrunner," Mayweather said. "He comes on strong in the first six rounds and then he gasses out. We knew he would come out strong. That was our game plan, to relax and take our time. If there wasn't the controversy, the fight would've ended."
Mayweather turned the tide in the fifth round.
He landed a strong right that backed up Judah and then got his body shots and hooks going. By the end of the round, the fighters were cursing at each other, but Mayweather had Judah in trouble.
"We come from the same street," Mayweather said. "He called me 'Bitch.' I called him a bitch. He said what he said. I said what I said."
Mayweather wobbled Judah at the beginning of the seventh and Judah's nose was bleeding.
By the ninth, Judah's right eye was swelling and Mayweather was in complete control, outlanding Judah 28-2 in power shots in the round.
But then Judah landed the low blow and rabbit punch in the 10th and Mayweather's momentum came to a halt.
"I don't know if he did it deliberately," Mayweather said, "but Roger said during the week that if he did do anything, he was going to go in the ring like he did."
Judah said the low blow was unintentional.
"I was aiming for the body. I didn't mean to hit Floyd low," Judah said. "I had his number early on, but he's highly defensive. Mayweather is a good fighter. He's very quick. I make no excuses. He was the better man tonight. It was a good fight. I'd like to do it again."
With King howling about a rematch, Roger Mayweather clearly violating the rules and the fighters with no other obvious big-money fight that could be made for this summer, Judah may get his wish.
Dan Rafael is the boxing writer for ESPN.com.