David Morrell Jr. was sitting on a couch inside the large training center for Circle of Discipline boxers in Barnum, Minn. It was a light workout day in the run-up to Morrell's fight with Mario Cazares that takes place Sunday night at the Minneapolis Armory.

Morrell was known by his first name, Osvary, as an amateur boxer out of Cuba. This led to the nickname "O" among fellow Circle fighters such as such as Jamal James and their trainers, Sankara Frazier and his son Adonis.

Now 23, Morrell had 137 amateur fights and won 135, all before he defected from Cuba in the middle of 2018. This will be Morrell's fifth pro fight, a defense of the WBA interim world super middleweight that he won in his third.

That title fight was a 12-round unanimous decision over veteran Lennox Allen in August 2020. Morrell's other three pro fights were early knockouts.

Morrell was asked if he has a fighting style that's more suited for the pros than as an amateur. Through an interpreter, he said:

"I enjoy both. They have given me different experiences. This is my career now, so I'm adopting the pro style and training for longer fights."

Morrell's ability to adjust quickly in both areas has been close to dumbfounding for Joe Goossen, the analyst for Sunday's Premier Boxing Champions card that will be shown on Fox.

"He's not a hit-and-run amateur," Goossen said. "Even with some great fighters I've trained, it took a while to undo some amateur stuff in them — to teach them to sit on punches more, to fight on the inside as well as the outside.

"Morrell already has that."

Goossen paused and said: "I've made notes as always from watching videos of his fights. 'Follows left hands with power; turns his opponents; tight defense; great uppercuts; loves to dip and counter … fights like a seasoned pro.'

"A lot of fighters don't want to engage early; they want to stay on the outside and get themselves into the fight. This guy goes right at you. And he can be athletic on the move or right in front of you."

Morrell comes from Santa Clara, Cuba. Fans of Che Guevara can find an official monument to him and other revolutionaries in that city.

The young fighter kissed his mother, Betty Gutierrez, goodbye one warm night in 2018, made his rendezvous with a speedboat and headed for Mexico.

Morrell needed 18 months of living there before getting the papers to head for Miami, where he signed with Warriors Boxing and manager Luis De Cubas Jr.

Luis and his family have strong Minnesota roots. He persuaded Morrell to train here with the Fraziers and help to fuel a boxing scene at the Armory, along with James, another WBA titleholder.

De Cubas saw the combination of amateur experience and immense talent, and the plan was to get him on the fast track.

Goossen trained fighters, and his brother Dan was a prominent promoter before his death in 2014. It was family attached to the boxing credo for building up top prospects:

Don't get 'em beat early.

"I can't imagine putting one of my young guys in the ring for a 12-rounder with a guy who was 22-0 in his third pro fight," Goossen said. "But that's what they did with Morrell last August.

"Lennox Allen. Tough guy. Always dangerous.

"Two short pro fights, all those amateur three-rounders, and then he's going all 12 with Allen. And David was way ahead on points, and still going for the kill in the last three rounds.

"That showed me a fighter with willpower, determination and lung power. I can't wait to see him back in that great Armory of yours on Sunday, against Cazares, another unbeaten fighter.

"The guys Morrell has fought to start his pro career are like 65-15. And his fifth fight is a title defense. Incredible."

Boxing returns to The Armory on Sunday for the first time since Aug, 31, 2019. Preliminary fights (FS1, Fox Deportes) start at 5 p.m. The nationally televised card (Fox, Fox Deportes) starts at 7 p.m. The main event, featuring Minneapolis-based David Morrell Jr. defending his WBA super middleweight title against Mario Cazares, is scheduled for 9 p.m. Tickets are available on The Armory website.

Write to Patrick Reusse by e-mailing sports@startribune.com and including his name in the subject line.