Tito Ortiz faces Ken Shamrock in one of two big Ultimate Fighting Championship rematches on Saturday at the Mandalay Bay Resort and Casino.

“I know he hates my guts,” Ortiz, 31, says of Shamrock.

It’s called Bitter Rivals as UFC 61 returns the caged fighting format to Las Vegas where UFC heavyweight champion Tim Sylvia faces Andrei Arlovsky for the third time. The fight card will also be televised on pay-per-view television live.

Ortiz (14-4) and Shamrock (26-10-2) have a bit of history too. Both are part of the television reality show called The Ultimate Fighter that pits Ortiz’s team against Shamrock’s on a weekly basis. But even before the TV show the two had bad blood.

A few years back Ortiz and Shamrock battled in the octagon after both had spout venomous words toward each other publicly. In the match, Ortiz proved too much for his hated rival and captured a victory in 2003.

Shamrock, 42, wants revenge.

In the heavyweight bout, Sylvia (23-2) scored a first round knockout over Arlovsky (11-4) back in April in Anaheim in their second meeting. But not before he hit the deck first from an Arlovsky right hand. Sylvia got up and proceeded to stop the Belarussian with a single left uppercut. Now each has a knockout victory over the other.

Other bouts will feature welterweights Yves Edwards (28-9-1) facing Joe Stevenson (28-7). Heavyweights Frank Mir (8-2) meets Dan Christison (8-4); and middleweights Josh Neer (17-3-1) battles Josh Burkman (17-3).

IBF junior middleweight title fight

Don’t forget the big junior middleweight showdown between IBF titleholder Roman Karmazin (34-1-1) and challenger Cory Spinks (34-3) on Saturday. It’s been almost two years since Spinks lost the undisputed welterweight championship and he hasn’t fought since.

“I had some problems,” said Spinks, whose daddy is former heavyweight champion Leon Spinks.

Karmazin won the title by overwhelming former champion Kassim Ouma a year ago. The championship fight will be televised by Showtime.

Possible California Heavyweight Showdown

One rumor circulating in the local boxing world involves Riverside’s undefeated heavyweight Chris Arreola possibly meeting L.A.’s undefeated heavyweight Damian “Bolo” Wills some time in the fall. According to one source in Wills camp, the fight will be shown on ESPN. But the source in Arreola’s camp says it will be shown on HBO’s Boxing After Dark. Hopefully the heavyweight contest takes place in Southern California.

Oscar “the Boxer” Muniz

I ran into Oscar “The Boxer” Muniz in La Habra this past weekend. The former prizefighter was the first to give Philadelphia’s Joltin Jeff Chandler a loss back in 1983.

Until that time, Chandler terrorized the bantamweight division.

Muniz says he’s training fighters out of his home in La Habra and has a hot amateur prospect out of Murrieta.

Toney vs. Peter in L.A.

It’s official. James “Lights Out” Toney will be meeting hard-hitting heavyweight Sam “Nigerian Nightmare” Peter at the Staples Center in Los Angeles on Sept. 2. Toney will be defending his IBA world title and fighting for the number one spot on the WBC rankings. I saw Toney two weeks ago in Calabasas and he looked pretty good.

Percival vs. Lovato at Morongo

Fontana’s Heather Percival will be fighting New Mexico’s Monica Lovato in a junior bantamweight bout, says Al Franco of Two Feathers Promotions. The fight will take place on July 21 at Morongo Casino. Percival is rated number seven by the WBA. Lovato is ranked number six by the WBC.

Enrique Ornelas to Meet Sam Soliman

Middleweight Enrique Ornelas is close to signing a contract to meet middleweight contender Sam Soliman of Australia. Ornelas has been providing sparring for Sugar Shane Mosley who is a week away from meeting Fernando Vargas.

“Enrique allows me to cut loose on my punches,” said Mosley. “He’s getting quicker all of the time. He’s also moving a lot smarter.”

Mosley had Ornelas, Armando Velardez Jr. and Ben Tackie in his Big Bear Lake camp.

The Ornelas fight will take place in August, but no site has been determined.

Israel Vazquez vs. Jhonny Gonzalez in Sept.

WBC junior featherweight champion Israel Vazquez is close to signing a fight that would pit him against another Mexico City fighter Jhonny Gonzalez, the WBO bantamweight titleholder. Golden Boy Promotions CEO Richard Schaefer said the two would be part of the fight card on Sept. 16 in Las Vegas when Marco Antonio Barrera defends his WBC junior lightweight world title against Rocky Juarez once again.

Free Tutoring From Mayweather Sr.

World famous trainer Floyd Mayweather Sr. and AM 570 KLAC have joined to give a lucky listener the Ultimate Boxing Weekend Experience, highlighted by the opportunity to be trained by Floyd Mayweather Sr.  

AM 570 KLAC listeners will have a chance to win a training session with Floyd Mayweather Sr. and the boxing experience of a lifetime. Mayweather comments, “I’m the best in the North, South, East, and West.  I will train you like I train the champ Oscar De La Hoya.” Executive producer, Ed Sheftel says, “Now that Oscar De La Hoya has decided not to step back into the ring, just yet, trainer Floyd Mayweather needs to keep busy so what better way, then to train an AM 570 listener. AM 570 KLAC is the only radio station giving away this Ultimate Boxing Weekend Experience to one of its All Access Pass members.’’

The winner will enjoy a two night stay at MGM Grand plus two tickets to see “The Rematch” between “Sugar” Shane Mosley vs “Ferocious” Fernando Vargas on July 15th, along with an autograph glove from Mosley and Vargas and a guest appearance/interview on “Neutral Corner with Rich Marotta” live from MGM Grand. For more details log on to am570radio.com.