LAS VEGAS — Brock Lesnar is well on his way to becoming mixed martial arts' biggest name. As he showed in UFC 100, he's already its biggest jerk.

That's certainly good news for the UFC's bottom line, since fans of any sport love to hate a proper villain. It's not so good for the mainstream image of a sport that publicly claims it wants nothing to do with its heavyweight champion's pro wrestling-style theatrics in the main event at the league's landmark event Saturday night.

"That's not who Brock really is, and what he did out there is not real," UFC president Dana White said after the unflattering end to his league's otherwise successful weekend in its hometown. "You don't have to act like someone you're not. This isn't the WWE. I'm not trying to get someone to act all crazy so we'll do more pay-per-views. That's not what this sport is about."

After being chastened by White, Lesnar quickly regretted his bad-boy behavior during his second-round stoppage of Frank Mir for his first title defense. Although the UFC made more than $5 million at the gate while broadcasting the event in a record 75 countries, the former pro wrestler realized he did some damage to that shaky bridge between MMA's loyal fans and the skeptical general public that already has trouble separating the UFC from the WWE.

"I was so jacked up (because) I'm used to selling pay-per-view tickets," said Lesnar, who left the WWE several years ago. "I come from a business that is purely entertainment. I screwed up, and I apologize."

In just his fifth MMA fight after a winding athletic path through college wrestling, fake wrestling and the Minnesota Vikings' training camp, Lesnar first refused to touch gloves with Mir. The hulking 265-pounder spent most of the fight's two rounds on top of Mir, using his weight and wrestling skill to wear down Mir's defenses, before finishing with a relentless series of right hands to Mir's face.

Lesnar (4-1), who lost to Mir last year, then taunted his fallen opponent while Mir still sat on his stool, his face bloody and swollen. When the Mandalay Bay crowd booed, Lesnar made a two-handed obscene gesture, followed by a rambunctious interview in which he insulted a prominent UFC sponsor and made an off-color comment about his own wife.

When Lesnar finally left the octagon, White cornered him in a bathroom for a tongue-lashing that left Lesnar apologetic. Yet it didn't wipe the grin off his face while he drank a Bud Light, just moments after claiming he preferred Coors Light over the UFC sponsor, "because Bud Light won't pay me."

"The only thing I had against Frank was that he beat me (last year)," said Lesnar, who turned 32 on Sunday. "We both talked a lot of crap, and in the end, I was just amped up."

That's slight consolation to White, who claimed he was "blown away" by Lesnar's antics and poor sportsmanship. The UFC knows it still hasn't sold its respectable image to a widespread audience, and having a heavyweight champion who can't control his inner 14-year-old doesn't help.

"Brock is talented," White said. "He's accomplished something that nobody has ever accomplished (by winning the title so quickly). Let that speak for you, not what you saw out there. ... That's not who he is. I've spent time with this guy. He's a smart guy, but he gets in there, the (energy) starts kicking. The mouth is moving, but the brain isn't sending stuff to the mouth."

That mouth will keep running, however. With his legion of fans and haters who have followed him since the WWE, Lesnar probably is the UFC's biggest pay-per-view draw. UFC 100 has a chance to top 1.5 million buys, which would make it the biggest non-boxing PPV event.

While the UFC moves on to its next showcases in Philadelphia and Portland, Ore., White must decide when to put his misbehaving heavyweight champ back in the octagon. The UFC stable contains a handful of fighters who could pose a threat, although Lesnar's rapidly improving MMA skills make him more daunting by the month.

But White remains confident he'll eventually sign Fedor Emelianenko, the Russian heavyweight considered among the sport's top pound-for-pound fighters. Emelianenko fights in Anaheim, Calif., on Aug. 1 to finish his contract with Affliction, and White said he'll go after the Russian striker with an open wallet.

"Eventually, Fedor is going to be here," White said. "I want him to come to the UFC. ... We'll do Brock vs. Fedor, and it'll be a huge fight. He's obviously contractually obligated to fight (in Anaheim), and once that's over, we'll see how it goes."