Many say Floyd Mayweather Jr. landed a cheap shot in taking down Victor Ortiz with a controversial fourth-round knockout for the WBC welterweight title. 

A majority of the crowd at the MGM Grand Garden Arena in Las Vegas certainly did, hurling catcalls questioning the deciding blow landed by Mayweather. In extending his record to 42 wins in that many fights, the 34-year-old Mayweather landed what many call a marginally legal blow on Ortiz, knocking his opponent into a hefty glaze.

With his hands momentarily by his side in the fourth round, after a bizarre head butt, apology, hug and kiss exchange, Mayweather seized his distracted opponent's moment. Mayweather landed a hook to Ortiz's unprotected jaw. Then, as a woozy Ortiz looked to the fight referee, Mayweather cracked a right against Ortiz's chin, effectively ending the match as Ortiz was counted down and out.

As Mayweather claimed the WBC welterweight crown and a multi-million winner's purse, boos and catcalls rang out from the crowd of about 22,000 while the Internet lit up with fight night calls of a Mayweather cheap shot.

From a rules perspective, Mayweather's attack was undoubtedly legal since referee Joe Cortez says he had told the boxers to fight on after the bizarre butt and ensuing exchange, initiated by Cortez. And that's where any argument that Mayweather landed a cheap shot in taking down Ortiz stops.

Nobody said boxing isn't a brutal sport. It's a fight, after all. The law in the ring is the referee -- not a man's honor. When the objective is to knock the opponent woozy to claim a knockout, when the referee doesn't step in to stop the fight, the contest is certainly on.

Yes, Ortiz had his guard down after the butt and strange exchange. But he let his own guard down, momentarily dropping his hands to gather himself. That was the big mistake, since the fourth round was still underway, and the referee hadn't stepped in. Thus, the fault cannot be placed at the hands of Mayweather, who now holds the crown.

He did what any good fighter would do -- he pounced when he saw an opening, lashing Ortiz with a right that claimed the crown. No, it wasn't a cheap shot that Mayweather landed.

It was a perfectly smart and legal blow from a good fighter.