Juan Manuel Marquez had a horrible night against Floyd Mayweather Jr. in his last fight, at least in terms of boxing. A proud champion made a lot of money but was reduced to a patsy, as the scores made clear: 120-107, 119-108 and a generous 118-109, all in favor of Mayweather. Marquez landed 69 punches in the fight.

And no one was surprised. Marquez moved up two weight classes at 36 to face one of the best boxers of this era. It was boxing suicide.

Ten months later, though, Marquez doesn’t seem to have regrets. The several-million-dollar payday he received was long overdue considering his accomplishments and, he’ll tell you, he truly gave an impossible task his best shot.

Plus, THE RING lightweight champion remains a hot commodity with lucrative prospects — including a pay-per-view rematch with Juan Diaz on July 31 in Las Vegas — and plenty of motivation as he nears the end of his hall of fame career.

“I knew going into the [Mayweather] fight that it would be a difficult task,” he said through a translator on a conference call Tuesday. “What made it a little more difficult was the excess weight Mayweather had. He was about 15 pounds heavier [than Marquez] inside the ring. I felt good. I gave it my all. I hope everyone realizes I gave 100 percent.

“ÔǪ My theory is that to be the best, you have to fight the best. I’ll never go back on that.”

Marquez (50-5-1, 37 knockouts) certainly isn’t taking on a transitional opponent in his first fight since Mayweather.

He and Diaz (35-3, 17 KOs) engaged in the 2009 RING Fight of the Year, an epic battle with the typical ebb and flow of classic fights. Marquez seemed to wilt under Diaz’s constant pressure early in the fight only to rally and score a hair-raising ninth-round knockout.

Both of them have had setbacks since, Marquez the loss to Mayweather and Diaz two shaky performances against Paulie Malignaggi in an ill-fated foray at 140 pounds.

However, while Marquez’s status as an elite fighter is a giant question mark after moving up to welterweight and then back down to lightweight at 36, Diaz is perceived by many to be the fighter in more-serious decline even though he’s only 26.

No one will be surprised if Marquez wins. And if he does? He’ll be in demand because of his name-recognition and the perception that he’s beatable.

Junior welterweight titleholder Amir Khan, who along with Marquez and Diaz is promoted by Golden Boy Promotions, said he would like to fight the winner of the July 31 fight before later saying he’d like to face Timothy Bradley.

The Khan fight is particularly attractive to Marquez because it would give him an opportunity to become the first Mexican to win a belt in four weight divisions, something even the great Julio Cesar Chavez couldn’t accomplish.

“That’s very important,” he said. “It’s something that keeps me going.”

If Khan goes a different direction, the options are many. Michael Katsidis (Golden Boy) at 135; several 140-pounders, including Marcos Maidana and Victor Ortiz (both also Golden Boy); his countrymen Erik Morales (whom Marquez mentioned) and Marco Antonio Barrera; Ricky Hatton (another name Marquez brought up); and possibly Diaz again if the Houston native manages to win.

And, of course, there’s always the possibility of a third fight against Manny Pacquiao.

Marquez would rather not look into the future, though.

One reason he has climbed to the pinnacle of the sport is that he’s a professional. And professionals take every fight seriously — especially a Fight of the Year rematch. We can speculate all we want but all he sees is Diaz.

“Right now my mind set on July 31,” he said. “After July 31, we’ll sit down and see what’s next in the future.”

They’ll be plenty to talk about.

Wish list: Marquez was asked who he would like to fight if he could simply choose an opponent. His first choice is no surprise: Pacquiao, the opponent of choice for everyone near his weight division because of the money involved.

Marquez probably has a more-legitimate claim to that fight than most, though. The two engaged in two hotly contested and controversial fights in 2004 and 2008. They drew in the first fight, after Marquez went down three times in the first round, and Pacquiao won a split decision in the rematch.

Many believe that Marquez should’ve been awarded decisions in both fights.

“That’s my desire,” Marquez said. “I want it so badly. I want that third fight with him before my career ends.”

Marquez probably shouldn’t hold his breath, though.

“Pretty much all the boxing writers at the post-fight press conference, people who saw it live, thought Marquez won the second fight but he didn’t get the decision,” said Richard Schaefer, CEO of Golden Boy. “I was there. I was pretty upset. I had some heated words with Bob Arum [of Top Rank, Pacquiao’s promoter]. It wasn’t right. There has to be a third fight.

“Arum didn’t want to hear anything about it then, though. I’m sure he doesn’t want to hear anything about it now.”

Marquez also mentioned Morales and Hatton as possible opponents.

At a loss: Schaefer was asked recently whether he thinks the fact both Marquez and Diaz are coming off losses will harm the promotion in any way.

“It’s interesting,” he said. “In UFC, it doesn’t matter if you win or lose. Some of their champions have just as many losses and wins. Still, people turn out en mass to watch their cards. Why? Because they want entertainment. The fans just want action. And boxing fans know they’ll get action in this [Marquez-Diaz] fight. There’s no way in the world this is going to be a boring fight.”

Trainer loyalty: Nacho Beristain, Marquez’s longtime trainer, implied that he didn’t like the fact his fighter bulked up to 142 pounds to face Mayweather. He also doesn’t believe that Marquez should face Amir Khan at 140 if he beats Diaz, which has been discussed.

Marquez could fight as a heavyweight, though, and Beristain would be by his side.

“I wasn’t 100 percent on board with it but it was necessary for that fight,” Beristain said of Marquez’s decision to add muscle for the Mayweather fight. “ÔǪ What could be his (weakness) is he loves what he does, he loves to work hard, but at times he can exaggerate his work. He’s a fine fighter. He doesn’t need to overtrain to perform in the ring.

“In that fight, for instance, instead of working with weights a couple of weeks, he might’ve done it for four weeks. It was a little too much.”

And Beristain didn’t mince when he was asked whether jumping back up to 140 is a good idea.

“No,” he said. “Juan has a small physique. To compete at higher weights is very difficult. Yet I have to support him 100 percent. His performances and the respect he’s earned cannot be denied. I have to support him and go with him to battle.”

One hour free: HBO will broadcast two of the early fights on the Marquez-Diaz cards for free.

In one of the fights, Sakio Bika (28-3-2, 19 KOs) of Australia faces Jean Paul Mendy (28-0-1, 16 KOs) of France in a super middleweight title eliminator. In the other, welterweight prospect Frankie Gomez (4-0, 4 KOs) of East Los Angeles will fight an opponent yet to be determined.

Michael Rosenthal can be reached at [email protected]