ONTARIO, Calif. – Robert Guerrero and Andre Berto didn’t win any style points with their grueling, mauling 12-round welterweight showdown on Saturday at Citizen Business Bank Arena, but both young veterans earned a ton of respect for the heart and grit they exhibited throughout the HBO-televised fight.

Guerrero, a former featherweight and 130-pound titleholder, probably garnered the most respect of his 11-year career by outworking Berto to a decision victory by unanimous scores of 116-110. The 29-year-old native of Gilroy, Calif., scored knockdowns in the first and second rounds.

However, despite the knockdowns and suffering a nearly swollen-shut right eye from the first round on, Berto never stopped trying to turn the tide with explosive uppercuts and right crosses throughout the fight. The 29-year-old native of Winter Haven, Fla., fought with both eyes practically closed during the final four rounds.

If Berto didn’t show the world that he’s got a champion’s heart with his final-round rally against Luis Collazo or his gutsy effort in his thrilling loss to Victor Ortiz, the former two-time titleholder proved it by going toe to toe with Guerrero down the stretch while practically blind.

And Guerrero, who recently moved from lightweight to welterweight, proved without a doubt that he can hang with the best 147-pounders in the world by constantly pressing and mauling Berto while absorbing countless flush shots from the naturally bigger man.

Berto’s vaunted speed was not a factor in the fight because Guerrero smothered him from the onset. The immediate hard pressure may have surprised Berto, who seemed to be doing his best impression of the Floyd Mayweather shoulder roll during much of the bout. Berto grabbed Guerrero when the aggressive southpaw got too close but the supposedly smaller man did a smart thing by working his free arm – his left – during the mutual clinches.

Guerrero’s first-round knockdown was scored when he basically battered Berto to the canvas with his “free arm.” The second-round knockdown was scored when Guerrero nailed Berto with a right hook followed by a sweeping left while the squat boxer-puncher was against the ropes.

From that point on, what some fans expected to be a blowout victory for Berto became a down and dirty dog fight. Berto wasn’t cut any slack from Guerrero, who refused to back down, or from referee Lou Moret, who twice warned Berto for holding, early and midway through the fight. Guerrero was warned for low blows late in the bout.

It was that kind of roughhouse fight, and it suited Guerrero better than it suited Berto, who needed to box more from a distance in order to fully benefit from his superior speed and power.

He wasn’t able to do that and he paid a brutal price.

“I told Andre I was going to beat him down,” said Guerrero (30-1-1, 18 knockouts). “I had to keep my word. I had to fight him on the inside and work his body.

“He didn’t hurt me at all. He caught me with a few shots. He’s a strong guy and he punched hard but I have a great chin.”

Berto, who hadn’t fought since stopping IBF beltholder Jan Zaveck last September, said he regretted not testing Guerrero’s chin earlier in the fight but he was humble in defeat.

“The referee was warning me for a lot of things, so I was timid,” said Berto (28-2, 22 KOs). “He was coming in and holding and grabbing me every time I got close, but it is what it is. I came back from 15 months off and fought Robert Guerrero. At the end of the day he fought a great fight.”

Guerrero, who outpointed undefeated Selcuk Aydin in his welterweight debut in July, now has to be considered a legitimate 147-pound contender. Still, one has to wonder how the blue-collar grinder would fare against the sport’s elite welterweights – Floyd Mayweather, Manny Pacquiao and Tim Bradley.

Guerrero wants to find out. However, he’s promoted by Golden Boy Promotions while Pacquiao and Bradley are handled by Top Rank, and as everyone knows, those two promotional powerhouses don’t get along.

So that leaves you-know-who.

“I’m here, let’s do this Floyd,” Guerrero called out after the fight. “I just beat a great former champ. I feel I’m the best and can’t be beat. I’m unstoppable.”

Photos / Naoki Fukuda