WBC heavyweight champion Vitali Klitschko is defending his title against Riverside, Calif., native Chris "The Nightmare" Arreola on Saturday at Staples Center in Los Angeles (10 p.m. ET, HBO).

The 28-year-old Arreola is trying to bring a piece of the fractured world championship back to American soil for the first time since Shannon Briggs held an alphabet belt in 2007.

Klitschko is one of the greatest big men in boxing history and, despite the dearth of competition in the division for most of his career, ranks among the 25 greatest heavyweights of all-time. At 6-foot-7 and 250 pounds, he's an imposing physical specimen who boasts the highest knockout rate of any heavyweight champion in history (92 percent). He's never been knocked down or taken a standing count. It's not a stretch to suggest the 38-year-old could still be undefeated if not for bad luck with injuries: Both losses on his record came on injury stoppages while Klitschko was ahead on the scorecards.

After stopping Corrie Sanders for the vacant Ring magazine heavyweight title and defending it against Danny Williams in 2004, Klitschko left the sport citing injuries and political aspirations. In October 2008, Klitschko returned following a 46-month layoff and knocked out Samuel Peter for the WBC title. He defended that belt with a ninth-round TKO of Juan Carlos Gomez earlier this year.

The biggest knock against Klitschko is the competition he's faced -- a symptom of the era -- but the combined record of Klitschko's previous five opponents is 219-10 with 180 knockouts.

Arreola is a younger, up-and-coming fighter whose inexperience puts him at a disadvantage against a seasoned technician like Klitschko. Truthfully, he could have benefitted from three or four more fights before taking on an opponent as refined and clinical as Vitali. But as one of the two most prominent American heavyweights today (along with Philadelphia's Eddie Chambers), Arreola's title shot rang early.

Klitschko may have the highest knockout rate of any heavyweight champ in history, but Arreola's kayo percentage (89 percent) is nothing to sneeze at. The odds this fight is going the distance are astronomical.

A classic outside boxer with devastating counter-punching ability, Klitschko uses range to neutralize his opponents' jab -- a strategy that renders most fighters impotent. Both of Klitschko's post-comeback opponents could barely touch him: Sanders landed just 9-of-90 jabs (10 percent) while Gomez connected on just 2-of-54 (4 percent).

But Arreola isn't like most fighters: He doesn't have much of a jab to neutralize. He's a pressure fighter with plans on taking the fight to Klitschko from the opening bell. He throws a high volume of haymakers and often loops his punches, a flaw Vitali could exploit.

Arreola has reigned in many of his wild tendencies and improved his precision, landing better than 60 percent of his power punches in three of his past four fights. If the hometown favorite can get inside and hurt Klitschko early, it could be an interesting night. The biggest question remains Arreola's conditioning, a perpetual question given his doughboy physique. He weighed 239 pounds for the best performance of his career -- a third-round stoppage of Witherspoon -- but tipped the scales past 250 pounds in less dynamic performances against Walker and McCline. Arreola needs to be in the best shape of his career to have a chance for the upset.

If Klitscho can survive Arreola's initial onslaught, the outcome should be scientific. Arreola's 26 fights have lasted 77 rounds -- an average of 3.0 rounds per outing -- and he's never gone past the eighth. By contrast, Klitschko is a fighter with demonstrated late-round knockout power, content to batter an opponent with jabs before moving in for the finish. The longer the fight goes, the more the scales tip in Klitschko's favor.

Oddsmaker William Hill lists Arreola as a 6-to-1 underdog.

Klitschko, blessed with a sturdier chin than younger brother Wladimir, weathers Arreola's worst in the opening rounds. A shift from defense to offense in the middle rounds finds Klitschko wearing down Arreola with a steady diet of head shots. Near the midpoint of the fight, Klitschko stops the dogged challenger following a lengthy beating. Klitschko by seventh-round knockout.

"Hey, I would have made fun of me, too. Boxing is not a bodybuilding sport, plain and simple. Your body isn't going to win a fight."
--Arreola, on his paunchy physique

"I'm always in shape. It's never tough to get in shape. I don't drink, don't smoke, don't do drugs. I always, always maintain fitness."
--Klitschko, on his approach to fitness

"I think he has the right style to beat this guy Klitschko. ... This kid Arreola is not afraid to go in there and brawl."
--Longtime trainer, manager and promoter Bennie Georgino, on Arreola's chances

"While Arreola has power to spare if he hits you, I don't know that he can hit Klitschko. If anything, Arreola can be hit."
--Veteran boxing writer Bert Sugar

"[Arreola] has just never really been forced to challenge himself or push himself. He's just got away with the way he's been doing it because he's so strong. He's going to look way different because of his training. I'm just glad the stomach is falling off him. You can really see improvements."
--Darryl Hudson, Arreola's strength and conditioning coach

"It is a great opportunity and it should be taken advantage of. I hope Arreola wins. He has a hard punch, and he cannot be ruled out. But the current champion, Klitschko, has more power in his fists than any other fighter. It is a very tough fight for Arreola, but if he wins, all the success will be for him."
--Mexico's Pipino Cuevas, former welterweight champion

"The whole sport changes overnight if Chris Arreola wins."
--Dan Goosen, Arreola's promoter

"We live in a microwave society. It ain't about the family sitting at home with Grandma doing the cooking and you say you're hungry and your Mom says, 'In an hour.' Now it's hit some buttons and you got a four-course meal. That's why fighters get knocked out so early. They don't have a chance to become that sweet peach on the tree. They get picked too soon. You taste that peach and it's bitter. It wasn't ripe. They're pushed by thieving, conniving promoters because they need to produce something that's not there yet. You got to have something to sell so what they sell is, 'Maybe he's a darkhorse like Buster Douglas.' You got to make soup but you ain't got nothing. You know you got nothing but you still need soup, so you boil some hot water and salt. You know you got nothing but now it's soup."
--Former middleweight and light heavyweight champion Bernard Hopkins, on Arreola's premature title shot as a symptom of the problems in the heavyweight division

MANNIX: More flab than fit, Arreola looks to prove naysayers wrong