Two big fights on Saturday — three if you count the promoters

It’s personal, it’s business, it’s boxing.

Saturday night, the two most popular Mexican fighters will headline opposing cards in Las Vegas as rival promoters Top Rank and Golden Boy continue to duke it out.

Top Rank’s world middleweight champion Julio Cesar Chavez Jr. (46-0-1) will have his greatest test, meeting Argentina’s former champion and 2010 fighter of the year Sergio Martinez at Thomas & Mack Center.

Down Tropicana Avenue at MGM Grand, Golden Boy’s super-welterweight champion, Saul “Canelo” Alvarez (40-0-1), will defend his belt against gritty replacement opponent Josesito Lopez of Riverside.

Fight fans will have to choose one or the other. Revenues won’t be maximized. Grudges have intensified.

Top Rank Chairman Bob Arum and Golden Boy Chief Executive Richard Schaefer don’t care for each other.

The hostility dates to Schaefer’s business partner and boxing legend Oscar De La Hoya splitting from promoter Arum to start his own company, Golden Boy Promotions, and continuing through the promoters’ inability to create the craved Manny Pacquiao-Floyd Mayweather Jr. fight.

“It’s the greatest sport in the world, but the lousiest business because we’re trying to kill each other,” said Bobby Goodman, a former matchmaker for fight promoter Don King and head of boxing at Madison Square Garden. “It makes no sense to be chesty and try to make it a point when it’s going to cost everyone involved a lot of money.”

Since boxing ranks in popularity behind the major sports, it likes to place big fights on dates free of both internal competition and obvious conflicts with important events in the sports world. Also there are weekends boxing believes it owns, with Cinco de Mayo and Mexican Independence Day weekend at the top.

Arum said studies have found 33% of pay-per-view fights in the U.S. are purchased by Latinos between the ages of 18-29, with 60% of those audiences consisting of Latinos.

At the turn of the century, then HBO boxing chief Lou DiBella — now Martinez’s promoter — used to schedule monthly phone calls and quarterly lunches with his counterpart at Showtime, the late Jay Larkin, to avoid scheduling strife.

Now the head of HBO Sports is Ken Hershman, who used to hold that role at Showtime, and Showtime’s head is former Golden Boy attorney Stephen Espinoza, who has battled Arum in court.

“Showtime’s first response should not be to the sport,” DiBella said. “Their primary consideration is their network, their subscribers. That said, there’s a lot of self-destructiveness that happens in this sport. Saturday night will be a great night of boxing. But there has to be more cooperation.”

The race to have a fight on Sept. 15 after Golden Boy staged Floyd Mayweather Jr. versus Miguel Cotto on May 5 was intense.

“We had held that date for a long time, but we’re dealing with a nasty old man trying to make a point,” Schaefer said of Arum. “Why does he need to have his fight this night in Vegas when he knows we’re already there? Why? I guess if you’re 100 years old, this is what excites you. Being nasty.”

After Alvarez’s original opponent, Paul Williams, was paralyzed in a motorcycle crash, James Kirkland backed out over a purse dispute. Then, Schaefer said Alvarez would fight Victor Ortiz, but the former welterweight champion was upset by Lopez on June 23 at Staples Center.

“Anyone who knows boxing knows you don’t announce a fight until you have a fight,” Arum jabbed.

“Honestly, we were ready to get off the date and go to Oct. 6 when they had Williams for Canelo — that was a real fight. But after Chavez beat Andy Lee June 16, we knew he was ready for Martinez, and that’s a major fight that fans have wanted. We finalized our fight the Monday after, when they had no fight.”

Arum said the smart thing would’ve been for Schaefer and Showtime to shift Alvarez-Lopez to Friday, as Arum’s former rival Don King did when conflict arose in March 2000. King moved his fight, Felix Trinidad versus David Reid at Caesars Palace, and Arum kept Paulie Ayala-Johnny Bredahl on Saturday at Mandalay Bay.

“Why go head to head?” Goodman said in explaining King’s thinking back then. “Let’s swallow this … and do what’s best for boxing. Especially now, with mixed martial arts doing so well, why do we want to kill each other from within? Canelo is a future superstar, and there’s not enough stars in boxing. Why pull the rug out from under him?”

Believing that Las Vegas high rollers don’t arrive in town by Friday early evening, Schaefer opted to beef up the undercard, move to straight Showtime coverage instead of pay-per-view and not budge from Saturday.

“Of course, I crunched the numbers,” Schaefer said. “We believe it’s still going to be a huge night for us that will show everyone the strength of Canelo and the quality of this entire card.”

MGM Grand reported Tuesday it had sold about 10,500 tickets to Alvarez-Lopez, with a capacity near 15,000. More important, broadcasting an Alvarez fight in Mexico this holiday weekend was irresistible, said Schaefer.

The deal with Mexican television network Televisa is worth a $1-million payment to Alvarez, a Golden Boy official said. The bout will be broadcast at a Mexico City plaza event where Mexican President Felipe Calderon is scheduled to speak.

“Canelo’s fight against Mosley had better ratings than the Mexico-Brazil Olympic soccer game and was 10 points higher than what Chavez-Lee did,” Schaefer said. “His fights are a huge, huge thing in Mexico. There’s no doubt he’s the No. 1 draw.”

In the U.S., however, the riches trend to Chavez-Martinez. Arum said Tuesday that Thomas & Mack’s 19,000-plus seats had sold out, resulting in live-gate sales of more than $3 million. Fight officials also express confidence that more than 400,000 will purchase the fight on pay-per-view for $59.95 each. Martinez is a 2-to-1 favorite.

lance.pugmire@latimes.com twitter.com/latimespugmire