Floyd Mayweather basks in aftermath of knockout of Victor Ortiz

Floyd Mayweather Jr. enhanced his villainous image by the way he registered a fourth-round knockout of Victor Ortiz on Saturday night.

By striking the instant he was allowed to punch after referee Joe Cortez stopped action to deduct a point from Ortiz for a head butt, Mayweather landed a left hand to Ortiz’s face that stunned the welterweight champion from Ventura.

With Cortez and Ortiz caught off guard, Mayweather (42-0, 26 knockouts) then finished the fight with a devastating straight right hand to Ortiz’s jaw that sent the 24-year-old to la-la land.

“I spaced a bit,” said Ortiz, who asked Mayweather for a rematch, contending the punches were “not fair.”

Mayweather, 34, chalked up the ending to his advantage in experience, and expressed no remorse after the frustrated, beaten-to-the-punch Ortiz (29-3-2) bloodied Mayweather’s lip and mouth with the head butt.

“What goes around,” Mayweather said, “comes around.”

When HBO’s Larry Merchant tried to interview Mayweather after the fight, Mayweather suggested the 80-year-old boxing analyst talk to Ortiz “since you’ve never given me a fair shake.” Mayweather used an expletive and questioned Merchant’s knowledge of the sport, to which Merchant replied, “If I was 50 years younger, I’d kick your [rear].”

Mayweather didn’t exactly embrace Ortiz’s rematch request.

“If he feels it was a fluke, I’ll do the same thing again,” Mayweather said. “But he was slowly breaking down as each round went. He was going to go down, anyway.”

It’s more likely that Ortiz will end up as a participant in a welterweight tournament his promoter, Richard Schaefer, will propose to HBO and Showtime this week.

Schaefer signed former junior-welterweight world champion Devon Alexander on Saturday, and said Alexander, Ortiz, Marcos Maidana, Andre Berto, Paulie Malignaggi and Lucas Matthysse are candidates to participate in a 147-pound tournament that will help increase those fighters’ recognition.

Mayweather has more thoughts to ponder beyond a possible 2012 matchup with Manny Pacquiao, who fights Nov. 12 against Juan Manuel Marquez.

“I move when I want to move, and I fight when I want to fight,” Mayweather said.

First, he has to deal with his criminal case.

Mayweather is due in Clark County (Nev.) Court on Oct. 15 for a preliminary hearing in his multi-felony domestic violence case in which the mother of his three children and some of the children are alleged victims.

“The only thing I can do is keep my fingers crossed,” Mayweather said. “I chose the best team of attorneys I know. I know I haven’t done anything. People want to create something because of who you are. With that [domestic] case, I say, ‘Where are the pictures?’.

“The rest [claims by security guards] it’s a bunch of bull. These guys say they got beat up, but they could walk to the hospital? It’s not real.”

Mayweather said after the bout he was unsure how much time he’d be away from the ring.

“I hope it’s not this long,” he said, referring to the 16-month layoff before he fought Ortiz.

He spent several minutes of his postfight news conference expressing skepticism about the Pacquiao fight, even though their schedules are close enough to meet in May.

Mayweather again pressed Pacquiao to commit to Olympic-standard testing for performance-enhancing drugs — Pacquiao promoter Bob Arum says the Filipino superstar will — and continued insinuating Pacquiao has engaged in doping even though Mayweather faces a defamation lawsuit on that matter.

“To say a guy goes from 105 pounds to this, and it’s all natural … come on, man,” Mayweather said.

He chided Pacquiao for “fighting all my leftovers,” and lashed out at critics, complaining, “When I beat that little dude [Pacquiao], they’re going to say he was too small or too old. They never appreciate me.”

Mayweather said Pacquiao “doesn’t want to fight me. Once he loses, it’s over. They’re tricking y’all saying they’ll fight me. Don’t be tricked.”

Schaefer said he expects to discuss Mayweather’s future with the fighter and his representatives within the next two or three weeks.

One of the top alternatives to Pacquiao is England’s Amir Khan, the junior-welterweight world champion who could help create a major boxing event at London’s Wembley Stadium.

Mayweather said, “I’m more popular in England than Khan,” and added, “I’m loyal to MGM.”

What mattered most to Mayweather was victory, and he appreciated being told his speed, defense and counter-punching were as strong as ever Saturday.

“Did I look sharp?” he said, smiling widely.

lance.pugmire@latimes.com

twitter.com/latimespugmire