GILROY -- Even when Robert "The Ghost" Guerrero can't be seen in this hardworking agrarian town, the people here feel his presence.

It's probably because the boxer who earned his nickname long ago for an ability to disappear from opponents carries the spirit of his hometown wherever he goes -- including Las Vegas for the fight of his career Saturday night.

After years of toiling in the shadows of boxing's grandest stages, Guerrero has finally landed the big one, a championship bout against undefeated and ever-controversial Floyd Mayweather Jr. When Guerrero, 30, steps into the spotlight at the MGM Grand, trying to do what no fighter has done against Mayweather, an entire town will be in his corner cheering on its underdog native son.

Gilroy (population 49,528) embraces its biggest sports figure since NFL quarterback Jeff Garcia because The Ghost symbolizes the heritage of those who worked the fertile fields of this town.

"What he means to us is basically a lot of what this town was built on: starting from the bottom and working for everything he's got," said Fernando Sanchez, a family friend who boxed with Guerrero when they were kids.

That is why city officials already scheduled May 18 as a day to honor the boxer with a post-fight party that will include the band Santana and a proclamation from Mayor Don Gage. Win or lose Saturday night, Gilroy won't turn its collective back on the man who has won six world titles in four divisions since turning professional at age 18.

"Gilroy is what I know, it's where I'm from," said Guerrero, who lives downtown in a modest 1940s home with his wife and two children.

This Ghost story began long before title belts came to Gilroy. Guerrero's grandfather boxed professionally. His father Ruben, who has trained Guerrero for most of his career, is a two-time Golden Gloves winner.

Ruben Guerrero, a fence builder by trade, introduced his six sons to boxing when they were young. They first trained in sleepy San Juan Bautista in a warehouse called the Potato Shed, a building with corrugated metal siding that now is used to store insulation and antiques.

The Guerreros eventually moved their training outpost to Gilroy's former community youth center, now shuttered. Peering through a smudged window, Sanchez, the longtime family friend, pointed to the east side of the gym. It was there he used to watch young Robert Guerrero box "like a natural."

He earned his nickname at age 9.

"By the time I'm done hitting, the kid looks to hit back, and I was gone, off to the side," Guerrero once explained, "and they kept saying, 'Man, you're like a ghost.' "

When the Guerreros weren't training or at school, they accompanied their father to work, hauling sandbags and barbed wire fencing to ranches on the outskirts of town.

The parents made ends meet the best they could. Marcy Guerrero handled janitorial contracts for Moffett Field for nine years to help support her kids' boxing dreams. Older brother Victor had a few professional fights, but Robert was the only one to make it a career.

At 16, Guerrero was the youngest competitor at the 2000 U.S. Olympic boxing trials. He decided to turn pro two years later instead of waiting for the Athens Games in '04.

As a dangerous lefthander who can take a punch, Guerrero found it difficult to secure a big-money opponent such as Mayweather, the reigning WBC welterweight champion; Mayweather is widely seen as the best boxer of his generation but known more recently for his two-month stay in a Las Vegas jail cell for domestic abuse.

Three years ago, Guerrero missed significant time too, putting his career on hold when his wife Casey was stricken with leukemia. The boxer has cited his wife's recovery as confirmation of his unshakable Christian faith.

The family attends the Foothills Foursquare Church where Pastor Mark Wilson and the congregation pray for Guerrero before each bout.

Bob Tapella, right, shows off a poster that he was giving to Jim Shuster, left, while they were talking about boxer Robert "Ghost" Guerrero at
Bob Tapella, right, shows off a poster that he was giving to Jim Shuster, left, while they were talking about boxer Robert "Ghost" Guerrero at Shuster's restaurant Dutchman's Pizza in Gilroy, Calif., on Wednesday, April 24, 2013. Story on the roots of Gilroy native Robert "Ghost" Guerrero and what he means to the city of Gilroy as Guerrero embarks on the biggest boxing match of his career, when he meets Floyd Mayweather Jr. for the WBC Welterweight World Championship on May 4 in Las Vegas. (Nhat V. Meyer/Bay Area News Group) ( Nhat V. Meyer )

"What we should be doing is praying for Mayweather," Wilson said. "We don't want him to take too bad of a beating."

Guerrero's faith-based lifestyle, small-town roots and the way he handled the ordeal with his wife's illness have given him an angelic reputation in a violent sport.

But Guerrero's image suffered a blow last month when he was arrested at New York's Kennedy Airport after he tried to bring an unloaded .40-caliber handgun onto a plane. Guerrero presented a locked gun box to a ticket agent during check-in. The gun was registered in California but was not legal to carry in New York. His next court appearance is scheduled for May 14.

In a recent interview, the boxer declined all questions on the matter. According to the online publication Roopstigo, Guerrero likes to shoot guns to relieve tension. He brought the gun to New York during a promotional tour before heading to Vegas, where he had planned to visit a shooting range for a documentary film crew.

The incident hasn't cost Guerrero his reputation in Gilroy.

"We don't care, we know Robert," said friend Jim Shuster, owner of Dutchman's Pizza.

This grass roots' admiration starts with Bob Tapella, known around town as "Pool Hall Bob." One recent day at Dutchman's, Tapella arrived with a plastic container filled with Guerrero mementos. The one-time owner of Garlic City Billiards carefully handled each item as if it were a museum artifact.

His prize possession is a pair of boxing shorts that Guerrero wore in his first professional fights.

The trunks were made by Gilroy seamstress Ignacia Palmer, who can't wait for the Mayweather bout. She has posted a handmade sign at her Marie La Beau Designer boutique in downtown that reads: "Do you believe in the Ghost? We do."

In Gilroy, she's not alone.

Contact Elliott Almond at 408-920-5865 and follow him on Twitter at twitter.com/elliottalmond.