The super-fight between Oscar De La Hoya and Floyd Mayweather Jr. on Saturday night in Las Vegas may be the most anticipated boxing match of the 21st century, so far.

But for Eddie Chambers, it isn't even the most anticipated boxing match of the weekend.

Chambers, a Philadelphia heavyweight who is undefeated at 28-0, will fight tomorrow night in his first real step into the national spotlight. His match against Dominick Guinn, who not long ago was a title contender, will be televised on Showtime at 11 p.m. and will be in Vegas, where boxing writers from all over the world are assembled this week.

"Chambers has an opportunity to separate himself from the pack of young, undefeated fighters," says Steve Farhood, a boxing analyst for Showtime and a former editor of Ring magazine. "But opportunity doesn't come without some risk. Good for him that he's willing to tackle Guinn, who's a bigger, stronger, more experienced guy."

"This is obviously my toughest fight," the 25-year-old Chambers said yesterday from Las Vegas, where he has been trying to screen out the insanity of the weekend. "To me, this is a business trip."

Only two unbeaten heavyweights in the world have more wins than the 6-foot-1, 215-pound Chambers. He is ranked No. 14 in the world by the International Boxing Federation.

From mid-2002 through last summer, he fought 16 straight times at the Blue Horizon, building his record against opponents picked more to give him experience than serious threats. In his last bout at the Blue, Ed Mahone seemed so reluctant to fight that state boxing czar Greg Sirb briefly held up both fighters' purses. Chambers won by technical knockout in the fourth round.

In December, Chambers, who is trained by his father, Eddie Chambers Sr., and managed by former Bernard Hopkins cornerman Rob Murray Sr., signed with California promoter Dan Goossen, who accelerated the pace. In February, Chambers put on his best display yet, showing speed and power in pummeling previously undefeated Derrick Rossy.

In 2005, Guinn (28-4-1) went the distance in a loss to James Toney, but he is 5-4-1 in his last 10 bouts.

"This is a step up to the next level and hopefully the next level after that," Chambers says.

"Whether Chambers can compete with heavyweights like the Klitschkos [Wladimir and Vitali] is another question," Farhood says. "For a 215-pound heavyweight to succeed at the highest level, he's going to have to be almost perfect on defense. Landing five shots and getting hit by one might not be good enough."

For now, Chambers is just happy to be where he is this weekend. "It's happening," he says. "All I can say is, it's happening."