You can never leave your guard down in a boxing ring.

In perhaps one of the most controversial endings to a pay-per-view fight in recent years, Floyd Mayweather Jr. ended Saturday night the same way he entered it, undefeated. “Pretty Boy” Floyd Mayweather, 34, took on “Vicious” Victor Ortiz, 24, in the MGM Grand in Las Vegas.

The fight opened with an introduction from the legendary announcer Michael Buffer. And in the tale of the tape, the slight advantage went to the taller, heavier, and younger Ortiz.

However, before the opening bell, Mayweather appeared to be extremely confident.

In any event, the opening round began slow as the two fighters sought to catch a feel for the other’s fighting style. Even with a slow start,,  there appeared to be no “ring rust” for the 34-year-old “Pretty Boy” who was coming off a 16-month lay off.

In round two, the action picked up. Mayweather’s speed began to take form, and he began to take control of the fight. The art form and foot work began to take over and the great counter puncher seemed to hit with extreme accuracy. Ortiz was the aggressor, however Money Mayweather still appeared to be in control of the fight.

By round three, Mayweather’s dominance became more and more apparent when he landed four times as many punches as Ortiz. Mayweather became increasingly difficult to hit and going into round four, Ortiz looked tired from chasing the quicker and more skilled Mayweather.

Early in round four, Mayweather landed a hard shot that appeared to hurt Ortiz. For the majority of the round, Mayweather maintained control, until stumbling late in the round.

The fight was delayed due to a dirty head butt by a frustrated Ortiz, followed by a controversial and dramatic ending with a devastating two-punch knock out combination by Mayweather with one second left in the fourth.

It took two seconds for the punches to land, yet it kept Ortiz on the ground for the rest of the night.

In the fight, Mayweather landed 73 punches, which was 35 percent of his punches thrown. While Ortiz found it difficult to touch his opponent and only landed 26 shots, which was only 18 percent of his punches thrown.

A two-punch combo that Ortiz never saw coming was a topic of debate for a brief moment.

In the post fight interview with Larry Merchant, Money Mayweather avoided the topic of the controversy of the final punches.

“I was victorious. If he wants a rematch he can get a rematch,” was all Mayweather had to say when asked about the dramatic finish.

However, perhaps the most memorable part of the night was the post-fight interview with Larry Merchant where Mayweather cursed out HBO’s long-time boxing commentator in front of millions of fans.

“You ain’t s***,” Mayweather called to Merchant after the legendary sports commentator claimed he took a cheap shot at Ortiz.

Boos from the crowd may have shown the disgust of the controversial ending and post fight interview.

In all, the dominant performance by Mayweather was completely overshadowed by the controversy that surrounded the late moments in the fight and the harsh confrontation that followed it. The night definitely ended leaving boxing fans with more controversy than anyone expected to see.

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• Trumaine McCaskill, Opinion Editor