Mike Chiappetta • E-mail

B.J. Penn said he would rid the sport of cheaters one at a time. First mission, accomplished.

Penn battered Sean Sherk with superior striking and scored a technical knockout of Sherk after the challenger was unable to continue following the third round at UFC 84.

Penn was the betting favorite prior to the fight, but the match -- emanating from the MGM Grand in Las Vegas -- didn't quite go according to plan. While Sherk has made his reputation on wrestling and takedowns, he only committed to one takedown over the course of the fight, was unsuccessful, and chose to engage Penn from the outside.

With the champion having a significant reach advantage, it was a bad strategy, as Penn peppered Sherk from the outside with strong jabs and uppercuts. Penn clearly and cleanly won the opening two rounds of the scheduled five-round fight with his striking, and was on his way to winning the third from Sherk, when he landed a perfect knee to the jaw with about 10 seconds to go in the third. Sherk immediately crumpled to the ground, and Penn capitalized with punches from the mount as the round ran out and the horn sounded.

As it went off, Penn rose to go to his corner, but Sherk stayed prone on the mat. Referee Steve Mazzagatti looked over Sherk, the former champion, and he wasn't moving, so Mazzagatti deemed him unable to continue, and waved the fight over, keeping Penn as the champ.

Immediately, with the win, Penn made mention of moving up in weight and fighting UFC welterweight champion Georges St. Pierre, who just earned the title with his win over Matt Serra last month.

"Very, very satisfying," Penn said.

After plenty of pre-fight feuding, Penn shook Sherk's hand and congratulated him on a good fight.

The bad blood stemmed from Sherk's previous positive steroids test after defending the belt against Hermes Franca at last July's UFC 73 (Franca also tested positive for steroids).

Prior to the bout, Penn had promised a victory, saying he was determined to cause Sherk suffering for his transgressions against fair play.

In the night's other feature bout, Tito Ortiz said good-bye to the octagon and the UFC after falling to Lyoto Machida via a unanimous decision loss.

Ortiz did not go quietly. After losing each of the first two rounds in close fashion, Ortiz nearly caught Machida in a triangle choke, then transitioned to an arm bar as the third and final round neared a close. Machida barely escaped and held on for the win.

It appeared that had Ortiz held the triangle or moved to top mount, he would have had better opportunity to finish the fight, but instead he chose the arm bar, which Machida escaped from.

"I was thinking, 'I'm going to die, but I'm not going to tap," Machida said after the fight.

The Brazilian also had a great moment early in the first round, when he scored a takedown with seconds to go and trapped Ortiz's right arm as he dropped punches. Ortiz was able to last the final few seconds of the round.

The crowd -- surprisingly pro-Ortiz -- gave the former UFC light-heavyweight champion and MMA pioneer a huge ovation after the fight. Machida proclaimed his opportunity to fight Ortiz "an honor," and Ortiz thanked the fans for 11 years of glory, saying he still hoped to fight for three more years.

"A lot of the stuff that happened before, between me and Dana White, it's all bull***," said Ortiz, wearing a T-shirt that read, 'I did It My way.' "It's just hard feelings we have towards each other. It's personal. The Fertittas have been awesome people, what they've done for the UFC, so I have to thank them. I gave 11 years in this octagon. It's too bad I'm leaving. I'm going to greener pastures I hope in the future."

In another feature bout, Wanderlei Silva got back to his winning ways by knocking out Keith Jardine in just 36 seconds.

Silva, nicknamed "the Axe Murderer" for previous destructions, rocked Jardine early when he got inside, then earned full mount and rained down unanswerd punches before the fight was stopped.

In other key results, Thiago Silva stayed unbeaten, moving to 13-0 by knocking out Antonio Mendes in a light-heavyweight tilt. Also, highly touted heavyweight Shane Carwin knocked out Christian Wellisch in just 44 seconds. In addition, Rameau Thierry Sokoudjou scored a first-round knockout of Kazuhiro Nakamura.

Full UFC 84 results
B.J. Penn def. Sean Sherk via TKO, 3rd Rd.
Wanderlei Silva def. Keith Jardine via KO, 1st Rd.
Goran Reljic def. Wilson Gouveia via TKO, 2nd Rd.
Lyoto Machida def. Tito Ortiz via unanimous decision
Thiago Silva def. Antonio Mendes via TKO, 1st Rd.
Shane Carwin def. Christian Wellisch via TKO, 1st Rd.
Dong-Hyun Kim def. Jason Tan via TKO, 3rd Rd.
Yoshiyuki Yoshida def. Jon Koppenhaver via anaconda submission, 1st Rd.
Rich Clementi def. Terry Etim via unanimous decision
Rameau Thierry Sokoudjou def. Kazuhiro Nakamura via KO, 1st Rd.
Rousimar Palhares def. Ivan Salaverry via arm bar submission, 1st Rd.

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