Mayweather defeats Ortiz by KO in Round 4.

Floyd Mayweather Jr. (42-0, 26 KO) won the WBC welterweight title from Victor Ortiz (29-3-2, 22 KO) tonight at the MGM Grand in Las Vegas, Nev.

CompuBox saw Floyd landing 73 of 208 punches while Ortiz landed only 26 of 148.

Mayweather had his way with the 24-year-old before landing a brutal combination to put Ortiz down and out on the canvas in Round 4. It didn't come without controversy.

"I got hit with a dirty shot, and it's protect yourself at all times," said Mayweather during the post-fight interview. "I hit him with left hook, right hand, and it ended the bout."

The end came after Ortiz intentionally head-butted Mayweather while he had him in the corner. Referee Joe Cortez deducted a point immediately, but before restarting the fight, both boxers embraced for a second to touch gloves before Mayweather threw the knockout shots.

"It's protect yourself at all times," Mayweather continued. "He did something dirty. If he want a rematch, we can get a rematch."

Ortiz didn't leave the ring without a smile on his face. He didn't admit to headbutting Mayweather, but the replay showed it was intentional.

"I was called to break by the referee so I did as I obeyed," said Ortiz. "I looked up and boom, I was out."

"There's two ways to look at it but as far as I was concerned I came here to entertain the fans and I think they were entertained. There was a miscommunication with the referee but nobody is perfect and this was a learning experience."

"I'm sorry for that," Ortiz continued. "It happens. I'm not perfect."

Undercard Results from MGM Grand in Las Vegas, Nevada:

Saul Alvarez defeats Alfonso Gomez by TKO in Round 6 to retain WBC light middleweight title.

Erik Morales defeats Pablo Cesar Cano by TKO in Round 10 to win the WBC light welterweight title.

Jessie Vargas defeats Josesito Lopez by split-decision to improve his undefeated record to 17-0.

source: Blake Dreisbach -Bleacherreport