Jesus Cuellar’s lessons as a jockey help make him a featherweight champion

It might seem like a primal scream when boxer Jesus Cuellar shouts a Spanish word to celebrate another victory in the ring.

“Forastero!” is Cuellar’s traditional call, a heartfelt tribute from the current World Boxing Assn. world featherweight champion to the one who taught him how best to maximize his athletic skills.

Now 29, Cuellar (28-1, 21 knockouts) still summons that inspiration, which he will need Saturday night in the most important bout of his life, a 126-pound title defense at Galen Center against former three-division world champion Abner Mares.

As a teenager, Cuellar was a jockey.

Forastero was the thoroughbred horse Cuellar’s family owned and that he raced in Buenos Aires. Cuellar estimates, without access to race records, that he rode Forastero in 37 races with only four losses.

“He didn’t like to be in the back. He’d always get closer and closer [to the front], and when he was close to the finish line, that was my favorite part because he would always give his all, even if he was behind,” Cuellar said through a Spanish interpreter. “I never needed to hit him with the whip. That horse would just explode at the end. He had a lot of heart.”

Cuellar said he convinced his father, Pacifico, to let him ride horses at age nine, and by 14 came the purchase of Forastero, which translates to English as “stranger” and is a cocoa-bean-bearing tree. Cuellar would both race the horse and ride it through town to the boxing gym for his training sessions.

While racking up victories in the ring, Cuellar was advancing as a rider.

“I was pretty good. I could beat my friends with their own horses. I know how to handle horses. I rode polo horses too,” he said.

Cuellar said his success atop Forastero was noticed and he was offered a contract to ride professionally before he turned age 18.

It was leading to a defining career choice because Cuellar was dominant in the boxing ring, thriving in Argentina’s national amateur competition.

Two days before a national 126-pound boxing final, however, Forastero suffered a fatal heart attack.

“I had one loss in Argentina and that was the one, my only loss in 300 fights, because my horse had died on the Friday before and I was so upset and depressed,” Cuellar said. “I didn’t want to fight, my trainer told me I had to. I fought and fought, but I lost.”

While Cuellar thought it’d be difficult to maintain a jockey’s weight of around 106 pounds, his horse’s death proved too emotional to handle and he quit riding, “immediately,” he said. “I was done.”

At 21, Cuellar turned professional. He made his U.S. boxing debut five years later, with a second-round knockout in 2014 of former featherweight champion Juan Manuel Lopez, then winning the belt by knocking out Vic Darchinyan last year.

Not only does Cuellar’s apparel include “Forastero,” the boxer tattooed his horse’s name on his left forearm.

“Have you ever seen my videos when I’m fighting?” Cuellar asked a reporter recently. “I’m confessing to you what I scream. People don’t know what I’m doing or what I’m saying, but I’m bringing my horse back alive, just like we’re back at the finish line. Sometimes, I start crying. I feel him inside my heart.”

Cuellar said he’d relish a chance to race again, but admitted when he saddled a horse last December for the first time in 10 years, he was overcome with emotion.

On Saturday Cuellar faces the veteran Mares (29-2-1, 15 KOs), who plans to counter Cuellar’s power and aggression with supreme boxing skills.

“We’re in against a tough opponent, but the higher-quality opponent, the better [Cuellar] does,” his new trainer, Freddie Roach said. “We’re going to take it to him. [Cuellar] is very aggressive and a very hard puncher, with both hands.”

With Showtime televising the main event in a division that ranks as one of the sport’s most talented, Cuellar hopes to build his reputation.

“I know [Mares] is going to give it his all, but I know I’m better than him. I have a bigger heart. I’m going to win,” Cuellar said. “People don’t really know about me, but now that I’m here, they’ll know I’m a warrior. I expect to do big things.”

lance.pugmire@latimes.com

Twitter: @latimespugmire