There’s a big fight taking place Saturday in Las Vegas that features boxing’s biggest star, middleweight champion Canelo Alvarez, going up in weight to challenge WBO light heavyweight world titleholder Sergey Kovalev.

But that’s not the only fight boxing fans should keep an eye on this weekend.

Miguel Berchelt puts his WBC junior lightweight world title on the line against Jason Sosa in the main event of a Top Rank card (ESPN, ESPN Deportes 10:30 p.m. ET) in Carson, California. And on the Canelo-Kovalev co-feature, 2017 ESPN prospect of the year lightweight Ryan Garcia will face power-punching Romero Duno in a highly personal battle (DAZN, 9 p.m. ET).

Canelo-Kovalev will get most of the attention, but here’s why your eyes need to be on Berchelt-Sosa and Garcia-Duno, as well.

Berchelt is elite

Berchelt himself is a world-class fighter. Ranked No. 1 by ESPN at 130 pounds, Berchelt has a solid set of victories on his résumé, including his title-winning fight against fan-friendly Francisco Vargas at the beginning of 2017. Since then, Berchelt has defended the green belt against the likes of Takashi Miura and Miguel Roman and, in his most recent outing in May, dispatched Vargas in the rematch with a sixth-round TKO victory.

Since a shocking, first-round TKO loss in 2014 to Luis Eduardo Florez, Berchelt has rebounded with 15 consecutive victories (14 by stoppage). He has crafted himself into a 5-foot-7 windmill that overwhelms his foes with a vast array of punches.

Berchelt has the size and range of a lightweight and wears down foes with his steady attack. It’s going to take a very good fighter, on a very good night to take his title.

The rivalry

This is not exactly Salvador Sanchez-Wilfredo Gomez, Julio Cesar Chavez-Edwin Rosario or Oscar De La Hoya-Felix Trinidad, but this is another chapter in the rich history of boxers of Mexican and Puerto Rican heritage in boxing.

There is always a good deal of nationalistic pride in these matchups. No matter how big or small the stakes are, each side wants to add to its victory tally in this intense rivalry.

“It’s the classic Mexican-versus-Puerto Rican rivalry,” said Berchelt. “And that kind of fight never disappoints.”

Sosa isn’t just another opponent

Sosa, of New Jersey, is no stranger to the upper echelon of boxing. He earned a majority draw against Nicholas Walters (who was 26-0, at that time) in 2015, and then captured a portion of the WBA 130-pound title by stopping Javier Fortuna in 2016. After one title defense against Stephen Smith, Sosa (23-3-4, 16 KOs), 31, was stopped by Vasiliy Lomachenko in 2017 in seven rounds, and later that year was the victim of a controversial decision loss to Yuriorkis Gamboa.

“You name these guys and these are some of the best fighters in boxing,” said Sosa.

Sosa heads into Saturday’s bout on a three-fight winning streak, having earned unanimous decision victories over Reynaldo Blanco and Moises Delgadillo and a TKO7 against Haskell Lydell Rhodes.

Bigger and better things ahead

Not to overlook Sosa, but a showdown between Berchelt and former featherweight world titlist Oscar Valdez would be a gem of a fight in 2020.

Valdez, the WBC top-ranked junior lightweight, faces the seventh-ranked Andres Gutierrez on Nov. 30 in Las Vegas. The winner of that fight will be the mandatory challenger for the Berchelt-Sosa winner.

“I hope [Valdez] wins, I want to fight him next year,” Berchelt said. — Steve Kim

Garcia vs. Duno heating up

Garcia, one of the most popular young fighters in boxing, faces Duno in a dangerous bout on the Canelo-Kovalev undercard. Why? Garcia absolutely insisted on fighting Duno.

Garcia had spent several weeks training to fight Avery Sparrow on Sept. 14, but when Sparrow was arrested the day before the fight, the bout was canceled.

Desperate to salvage the fight, since it was Garcia — a fan favorite with 3.6 million Instagram followers — who was selling many of the tickets, Golden Boy Promotions executives went to Garcia’s team and asked if he would be willing to instead fight Duno on short notice. Duno (21-1, 16 KOs), 24, of the Philippines, was already on the undercard.

Duno, a very good puncher and prospect in his own right, was very happy to take the fight because he views Garcia as a guy on his way to the top and wants to upset him.

“I never turn down any fight Golden Boy gives me,” Duno said. “Every opponent they gave me, no questions. Short notice, as long as I’m in good shape, I will fight anyone. When they offered me that fight, I said yes immediately. I didn’t even think about it.”

“When we lost Sparrow, we were grabbing at straws and trying to repair the damage,” Golden Boy president Eric Gomez said. “Duno stuck out like a sore thumb — same weight, already on the card, right-handed, licensed and a good fight. We made a move to make that fight to salvage Ryan’s fight.”

Garcia (18-0, 15 KOs), 21, of Victorville, California, and his team didn’t see it that way and turned down the bout. They were unhappy with the late change and not getting the kind of money they wanted to make the switch.

After not taking the fight, Garcia was trashed on social media, by fans and industry leaders alike, for supposedly ducking Duno. Even his promoters Gomez and CEO Oscar De La Hoya publicly shared their displeasure.

Garcia lashed back out at his promoters, saying he never had a problem fighting Duno but wanted proper preparation time and compensation. That feud nearly led to a breakup between Garcia and Golden Boy.

The next night, Garcia watched the broadcast and saw Duno’s fight, a seventh-round knockout of Ivan Delgado, and was incensed.

“Duno wore a shirt [into the ring] that said, ‘Ryan Garcia is ducking me,'” Garcia said (actually, the T-shirt read, “Ryan Garcia next stop running”). “I knew I wanted him. Now, it’s on the stage I want it on, and I’m excited.”

Days later, Garcia and Golden Boy worked out a five-year contract extension that gave Garcia a big pay raise. They also agreed that his first bout of the new contract would be on Canelo’s undercard. Garcia insisted the first fight had to be against Duno.

Garcia will get $250,000 (up from $50,000) for the fight with Duno, who will earn $50,000.

“A win just proves to everybody that people talk without knowing what they’re talking about. I was never afraid to fight,” Garcia said. “I want to win with complete control, outclass him every round, every minute, and not be touched one time. I will have that killer instinct in me. I feel this fight is gonna end in two rounds, and I never have given predictions, but I feel strongly about this.”

Garcia views the fight as the beginning of the next chapter of his career.

“My objective when I came in as a pro was to get everyone to know my name,” he said. “I wanted to build up my fan base, and that’s what I did with social media and some televised fights. Now my whole focus is getting my respect in the ring. Everybody knows me in boxing. I’m already a superstar.

“Now I want to be the best in the world in my division, in multiple divisions. I don’t even post much on social media [anymore]. I don’t even care anymore. I just want to be great.” — Dan Rafael