Gary Russell Jr. recognizes that one of his unbeaten younger brothers, Gary Antuanne Russell, isn’t a complete product.

The former WBC featherweight champion still feels that the hard-hitting junior welterweight contender can beat anyone in his division. Gary Antuanne Russell (15-0, 15 KOs) will work toward proving his older brother correct Saturday night, when he’ll battle Cuban veteran Rances Barthelemy (29-1-1, 15 KOs, 1 NC) in the 10-round opener of Showtime’s tripleheader from Barclays Center in Brooklyn.

“Rances is a great opponent,” Gary Russell Jr. said during an open workout last week in his hometown of Capitol Heights, Maryland. “Whoever wins this fight is getting a big leg up in their career. My brother is looking to take over the division. I don’t think there’s any fighter in the division who he couldn’t beat. He can run through these guys. All he has to do is listen, that’s it.”

Gary Russell Jr. always works his brothers’ corners, but Saturday night will mark the first time he’ll handle head trainer duties since the death of their father, Gary Russell Sr. The patriarch of their boxing family died May 23 at the age of 63 from complications related to Type 2 diabetes.

“I was always side-by-side, working with my father when it came to working with my younger brothers,” Gary Russell Jr. said. “Even before I was going to fight, if they were on my undercard, I would work their corners as well. I think my father was somewhat always preparing me for this.”

Gary Russell Jr., who lost the WBC featherweight title to Filipino underdog Mark Magsayo on January 22 in Atlantic City, New Jersey, is looking forward to guiding Gary Antuanne Russell through another meaningful fight.

“Your corner is your last line of defense,” Gary Russell Jr. said. “As a fellow fighter, I understand that. My brother is still learning to adjust on the fly. He’s learning, but there’s still things left to tweak.”

After Russell, 26, and Barthelemy, 36, open Showtime’s tripleheader at 9 p.m. ET, Brooklyn’s Adam Kownacki (20-2, 15 KOs) and Turkey’s Ali Demirezen (16-1, 12 KOs) are set to square off in its co-feature, a 10-round heavyweight bout. In the 12-round main event, Philadelphia’s Danny Garcia (36-3, 21 KOs), a former junior welterweight and welterweight champion, will make his 154-pound debut when he opposes Phoenix’s Jose Benavidez Jr. (27-1-1, 18 KOs).

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.