LAS VEGAS – Mario Barrios will make his debut at the welterweight limit of 147 pounds when he faces Keith Thurman on Saturday night.

Barrios also was knocked down three times and stopped by a significantly shorter opponent who moved up in weight when Barrios lost his last fight seven months ago. Though Thurman also lost his last bout by split decision to a shorter southpaw, the legendary Manny Pacquiao, the former WBA/WBC welterweight champion seemingly has obvious advantages over Barrios as their FOX Sports Pay-Per-View main event nears.

Thurman made it clear, however, that the last thing he could afford to do against a taller, tough opponent is underestimate him, especially since Thurman hasn’t fought in the 2½ years since Pacquiao edged him by split decision in their welterweight title fight.

“Mario Barrios, he still has a height and reach advantage over me,” Thurman told “Obviously, I lost to Pacquiao. Very close fight, great fight. But, you know, there’s no way I’m gonna underestimate a lightweight ever again. You can’t underestimate lighter fighters. It’s the fighter that matters, not the weight class, right? And we’ve seen it throughout boxing. We watched what Floyd did and how he dominated the welterweight division. We all know he wasn’t no real welterweight. The boy was eating McDonald’s and making 147. So, I’m not underestimating Mario Barrios.”

The 33-year-old Thurman, of Clearwater, Florida, has been impressed by Barrios’ run in the junior welterweight division. San Antonio’s Barrios was a secondary WBA champion, but the previously unbeaten Barrios fought courageously against Gervonta Davis (26-0, 24 KOs), a knockout artist who stopped him in the 11th round of their June 26 bout at State Farm Arena in Atlanta.

The 5-foot-10 Barrios, 26, was competitive versus Davis, who moved up from the lightweight limit of 135 pounds to battle Barrios for his WBA world super lightweight championship.

“I know he throws good combinations,” Thurman said. “I know he’s bringing some speed to the table, some athleticism. I know he’s got a good trainer. I know he’s got a good camp behind him. I know they’re coming off a loss, like me. So, just like me, they should be hitting that drawing board and really trying to fine-tune yourself and one-up yourself. I remember when Victor Ortiz lost to Marcos Maidana. Then he beat my boy Andre Berto, and nobody expected him to beat Berto because he’s coming off of a loss.

“[Ortiz] was the guy who, after the fight said, ‘I don’t know if boxing is for me.’ And then he came and put on such a terrific performance [a unanimous-decision win in April 2011]. So, you can’t underestimate fighters off of a loss. And I just look forward to the challenge that Mario Barrios is gonna bring.”

The 12-round bout between Thurman (29-1, 22 KOs, 1 NC) and Barrios (26-1, 17 KOs) will headline a FOX Sports Pay-Per-View event at Mandalay Bay’s MICHELOB ULTRA Arena. The four-fight show is scheduled to start at 9 p.m. ET and costs $74.95.

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