ATLANTA – Fighting Gervonta Davis wasn’t on Mario Barrios’ radar at all when Barrios boxed on Davis’ undercard October 31 in San Antonio.

Barrios didn’t even stay at Alamodome to watch Davis battle Leo Santa Cruz in the main event after Barrios beat Ryan Karl by sixth-round knockout that night in Barrios’ hometown. Saying that the unbeaten WBA super lightweight champion was completely caught off guard when he first learned Davis wanted to fight him next would be an understatement.

“I was very surprised to hear his name,” Barrios told BoxingScene.com. “But I give him respect for wanting that type of fight, that type of challenge. But, you know, it’s a very dangerous challenge. It’s a big opportunity not only for myself, but for him as well.”

Baltimore’s Davis officially can become a champion in a third division by beating Barrios on Saturday night at State Farm Arena.

Nevertheless, Scotland’s Josh Taylor (18-0, 13 KOs), boxing’s undisputed 140-pound champion, is the WBA’s true champion in that weight class. Barrios owns that sanctioning organization’s secondary title.

While a 5-1 favorite according to most sports books, Davis (24-0, 23 KOs) will face a significant size disadvantage against Barrios (26-0, 17 KOs) in their Showtime Pay-Per-View main event (9 p.m. EDT; $74.99). The powerful southpaw stands nearly five inches shorter than Barrios, who has competed within the junior welterweight division for the past four years.

“It didn’t surprise me too much,” Barrios said of his size advantage. “I’ve been on cards with ‘Tank’ plenty of times. We’ve been around each other a few times, so I always knew the size advantage I had since they announced the fight. But, you know, it’s my job to go out there on fight night and use that advantage to the best of my abilities.”

The 26-year-old Barrios isn’t offended Davis chose him as his opponent for Davis’ first fight at the 140-pound limit.

“He probably picked me just because at the time, that’s when Taylor and [Jose] Ramirez were getting ready for their fight,” Barrios said in reference to Taylor’s 12-round, unanimous-decision win in their title unification match May 22. “There really wasn’t anything that was lined up for me. [This] would’ve been the easier route for them to just jump up and capture a title. But again, you know, he has a very difficult task in front of him. I feel they bit off more than they can chew. It’s my job to prove that come June 26th.”

The dangerous Davis has knocked out 96 percent of his pro opponents. Davis’ detractors wonder whether he’ll be the same devastating puncher at the 140-pound limit that he was when he viciously knocked out Santa Cruz (37-2-1, 19 KOs) with a left uppercut in the sixth round of their 130-pound title bout.

“I feel like that’s the question that everybody’s asking,” Barrios said. “We’re definitely going into this fight with the mentality that he is [as strong at 140 pounds]. We’re going into this fight expecting the best version of ‘Tank’ that anybody has seen. We’ve prepared for the hardest fight of my career. I’m just making sure I’m doing everything I can to stay focused and stay prepared to have another successful title defense.”

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