LAS VEGAS – The 21st century model Oscar De La Hoya will be unveiled Saturday night.

Guided by new trainer Floyd Mayweather Sr., the 28-year-old De La Hoya will box Arturo Gatti in a 12-round welterweight match, his first fight since he lost the WBC title on a split decision to Shane Mosley last June 17.

"If I had Mayweather earlier in my career, I would be undefeated and still champion," said the man who won an Olympic gold medal and world titles in three weight divisions. "It is a shame that I had the trainers I had before, but that is just the way things are."

De La Hoya's previous trainers have included Robert Alcazar, Emmanuel Steward, Gil Clancy and Jesus Rivera. Alcazar was head trainer for the Mosley bout, the second defeat for De La Hoya in his last three fights. The other loss came on a 12-round decision to Felix Trinidad on Sept. 18, 1999.

"It's great to be back," De La Hoya (32-2, 26 knockouts) said Thursday. "I feel very happy. Finally after so many years, we're doing things right. He (Mayweather) has pushed me like nobody else pushed me. I thank him for teaching me how to box."

"Until now, he had pretty much been doing things on his own and he did a great job on his own," said Mayweather, father of the WBC super featherweight champion. "Now I am teaching him what boxing is all about. If he did that good on his own, now that he has a good trainer, you are going to see a new and improved Oscar De La Hoya. I am teaching him defense and offense all together."

What boxing is all about for the 28-year-old Gatti is to attack.

"I'm going to fight my heart out," said Gatti (33-4, 27 knockouts), a former IBF junior lightweight (130 pounds) champion. "Oscar will be in a fight."

Gatti, a native of Montreal living at Jersey City, N.J., thinks his aggressive style and the fact that he has been cut in some fights are the reasons he was picked for De La Hoya's comeback opponent.

"I think he expects me to be an easy target," said Gatti, who has won four straight fights since being stopped by Angel Manfredy and twice outpointed by Ivan Robinson in his three 1998 bouts.

De La Hoya was a 30-1 favorite, and already plans to move up to 154 pounds and challenge Javier Castillejo, the WBC super welterweight champion from Spain, on June 9 at a site to be announced.

Trinidad is the WBA-IBF 154-pound champion, but will move up to 160 and challenge WBA middleweight champion William Joppy on May 12 in New York.

"I'm going to show the world I'm not just a bleeder," added Gatti, who said the only time he was cut by a punch and not by an elbow or a head butt was in the Manfredy fight. "I think I'll be stronger in the later rounds."

De La Hoya said he has done a lot of sparring because "eight or nine months out of boxing shows you can be a bit rusty."

During his layoff, De La Hoya recorded a record album, "Oscar De La Hoya," nominated for a Grammy for best Latin Pop Album of 2000.

After the De La Hoya-Gatti match, which will be shown on HBO, viewers will see a tape of Saturday's WBO heavyweight title defense by Vladimir Klitschko of Ukraine against Derrick Jefferson of Detroit in Munich, Germany.

Also on the MGM Grand card will be a WBO cruiserweight title defense by Vassiliy Jirov of Kazakstan against Terry McGroom of Little Rock, Ark.

It also will be De La Hoya's first fight for promoter Jerry Perenchio since he went to court and got out of a contract with Bob Arum, who has countersued De La Hoya.

De La Hoya's purse is $5 million; Gatti's $1.4 million.