Juan Diaz says he is motivated and focused on only one thing — winning another lightweight world title belt.

His quest to achieve that goal will continue when he faces Mexico’s Cesar Vazquez in the scheduled 10-round main event of Top Rank “Solo Boxeo Tecate” card Saturday night (UniMas, 11 p.m. ET/PT) at Casino Del Sol in Tucson, Arizona.

“I’ve been there before and I know what it takes to get back onto the big stage again. I am only fighting now for one reason — to win (another) world title. That puts a mark of importance on my fight Saturday night because I must win to get to where I want to go.”

Diaz (41-4, 20 KOs), of Houston, was once the lightweight division’s kingpin. From 2004 to 2008, he held a title and went on to unify three major belts before being upset by Nate Campbell via split decision in a bullring in Cancun, Mexico.

By late 2010, and having lost three of four fights, including twice to Juan Manuel Marquez and once to Paulie Malignaggi in their rematch, Diaz was retired, burnt out from boxing and moving on to concentrate on his successful trucking business.

But like so many fighters, the competitive drive never left Diaz, known as the “Baby Bull,” and he returned in 2013, rested and rejuvenated. He racked up five wins in a row using his typical relentless style and was set to face Japan’s Takahiro Ao for a vacant lightweight world title on May 1, 2015, the night before Floyd Mayweather-Manny Pacquiao, in a nationally televised fight in Las Vegas.

Diaz’s fight with Ao never happened, however, because Diaz tore his left rotator cuff during a training session. After 18 months out of the ring, Diaz returned in March and knocked out Fernando Garcia in the ninth round as he began another run to what he hopes will be a title fight.

Fight No. 2 of his latest comeback will come against Vazquez (27-3, 16 KOs), 30, who has won two fights in a row since losing three straight by knockout.

“I cannot — must not — have any setbacks. Winning is the only thing now. This is what I am dealing with when I fight Vazquez. I want big fights now. I want to wear the belt again.”

Juan Diaz

If Diaz takes care of Vazquez, Top Rank vice president Carl Moretti said the plan for Diaz is the same as it was before the shoulder injury interrupted his career — to step him up into a bigger fight and eventually get him a world title opportunity.

“There’s no question we want to put him in some type of bigger fight next,” Moretti said. “What that is unfortunately hasn’t been figured out yet. But if it’s a title fight, great. If it’s a title eliminator, great. Whatever it is, it will be a bigger step up, but I think as far as Saturday goes, we’re going to see somebody that is still fresh and somebody that has a lot left in the tank and is nowhere near the end of a career physically.

“You’ll see a non-stop pressure guy who throws a gazillion punches and swarms Vazquez and makes a great fight. Why should this fight be any different than his other fights?”

Diaz turned pro in 2000 at age 17 and still is only 32. He said he expects to win another title before he is done for good.

“At home in my trophy room I have spotlights beamed right on my world title belts,” Diaz said. “I have another spotlight ready to shine on my (next) world title belt. When you are a champion you are a different person. You are the champion. This motivates me now every time I get into the ring to train and every time I get into the ring to fight.

“I cannot — must not — have any setbacks. Winning is the only thing now. This is what I am dealing with when I fight Vazquez. I want big fights now. I want to wear the belt again.”