Andre Berto will try to beat odds vs. Floyd Mayweather Jr.

LAS VEGAS — The chances of Andre Berto’s unlikely win over Floyd Mayweather Jr. are hinged to the motivation he has taken from a career-threatening shoulder injury, to the counsel of his trainer and maybe even something about a woman.

Few expect the Florida-based, Bay Area-trained 32-year-old to threaten Mayweather’s unbeaten (48-0) record.

Berto is 3-3 in his last six fights, and lost by decision to Victor Ortiz and Robert Guerrero, who both were convincingly beaten by Mayweather.

In those losses, Berto kept coming forward and paid the price.

He was knocked down twice in the 2011 loss to Ortiz, costing him a shot at Mayweather. Then he suffered two swollen eyelids while getting decked twice more by Guerrero in 2012 to lose his second chance to fight Mayweather.

You can see Mayweather’s strategy from miles away.

After enduring criticism that his May win over Manny Pacquiao was a dud, Mayweather wants to reach 49-0 with a memorable 27th knockout victory.

“We’ll see,” Mayweather said with a slight grin when asked about Berto’s vulnerability to a knockout. “I’m going to go out there and do what I do and stay focused.”

At the MGM Grand, where the Saturday night fight will be staged, the race and sports book lists Mayweather as a staggering 30-1 favorite.

Berto’s response to the long odds is to point to his own recovery from a 2013 shoulder injury that kept him from lifting his arm and required an extended layoff and changed his attitude from entitled to humble.

His chance at a Hollywood resurrection story began in Ontario in March, when Berto knocked out Josesito Lopez in the sixth round.

He has been scorched by critics of a fight that was originally considered for a free showing on CBS, and now costs $74.95. Berto says he tried to tune out the negativity during an intense training camp in Oakland under Virgil Hunter, who also trains unbeaten super-middleweight Andre Ward.

“I’m over it all. I prepared myself to deal with it,” Berto said of the criticism. “I don’t read any of this.… How can another man tell me what I don’t deserve? I don’t comprehend it. I don’t engage it.”

While the opponent may be inconsequential when Mayweather is fighting at his peak, Berto wants to explore his puncher’s chance, vowing he’ll never be “calculating” or “standing around.”

“He has a great IQ,” Berto said. “You can be smart, fast, this and that, but one shot can change it all. This camp has definitely taken me to levels I haven’t been. I’m in great shape, mentally focused, I have this tunnel vision.”

Hunter has alluded to other motivation, “a beef,” he calls it, that might be connected to a woman both fighters know.

“Whatever score it is has to be settled,” Hunter said. “It’s given me a wedge to drive during the tough periods of the fight. I’m looking for a rumble, considering this might be Mayweather’s last fight and how Berto’s been discredited. It’s a diss.

“Andre has a resolve, a character under real tough circumstances that he never stops trying. Those are the first ingredients you look for in a boxer: Will he fight? I admire his journey so far.”

Hunter, a former probation officer who learned how to counsel those facing tension, has built a strong bond with his fighter in two years.

The trainer says he has taught Berto to respond to Mayweather’s psychological gamesmanship.

“From the time [Mayweather] walks out of the weigh-in, his entrance captivates the whole situation … it goes to the subconscious,” Hunter said. “Everyone feels the electricity and the other guy feels left out, like the role player.

“Then he leaves the dressing room … comes in and walks over the whole ring, goes in between everybody, around everybody, over here, there, ‘This is mine, I got control of this ring,’

“Bump into him. It’s not your ring. We’re here. … All of these things are important to circumvent that.

“All athletes can take it to another level. … If the opportunity of a lifetime can’t motivate you, you might as well retire.”

lance.Pugmire@latimes.com

Twitter: @latimespugmire