MILWAUKEE >> Anthony Pettis claimed the UFC lightweight title in his hometown Saturday night, beating champion Benson Henderson by armbar submission in the first round at UFC 164.

Pettis (17-2) ended Henderson’s 18-month championship reign in decisive fashion, catching Henderson (18-3) in an armbar while on his back late in the round at the Bradley Center.

"It feels amazing to be here," Pettis said. "I grew up coming to this arena and sitting in those nosebleeds. Milwaukee made Anthony Pettis. You really can’t write a better story than what happened right here tonight."

Pettis stretched out Henderson’s right arm and abruptly finished the rematch of their memorable WEC bout, beating Henderson for the second time. Henderson verbally tapped out of just his second loss in 19 fights — both to Pettis.

"The armbar was there," Pettis said. "I grabbed it and I heard him yell, ‘Tap, tap, tap,’ and that was it."

Heavyweight Josh Barnett won his first UFC fight in 11 years, stopping Frank Mir with a big knee to the head midway through the first round. Chad Mendes also stopped veteran Clay Guida in a meeting of 145-pound contenders.

Pettis climbed onto the cage to celebrate his win in a rematch of the fighters’ memorable meeting in December 2010, the last bout in the history of the now-defunct WEC promotion.

Pettis punctuated that back-and-forth fight by launching himself off the side of the cage for a gravity-defying kick that flattened Henderson and turned the fight in his favor, giving him a unanimous decision and the WEC title.

The "Showtime Kick" is among the most memorable feats in mixed martial arts history, but Henderson surpassed Pettis’ career in the ensuing years. He won the UFC lightweight title with a victory over Frankie Edgar early last year and defended the belt three times, twice by razor-thin split decisions over Edgar and Gilbert Melendez.

While Henderson turned himself into a points fighter with little inclination to knock out his opponents, Pettis kept fighting aggressively, but missed his own shot at the lightweight title with an upset loss to Guida before sitting out most of 2012 with injuries.

Pettis got this shot at Henderson when contender T.J. Grant dropped out of the matchup last month with a concussion.

Henderson had described his loss to Pettis as a "stain on my soul." He spent the first round rushing Pettis onto the cage and attempting takedowns before Pettis abruptly finished it.

"Anthony is tough, and tonight he proved himself to be a champion," Henderson said. "But I’ll be back."

Barnett (33-6) made stunningly quick work of Mir in his first UFC bout since March 2002, when he beat Randy Couture for the heavyweight title. Barnett was quickly stripped of the belt for a positive doping test, and his career wandered through Japan and several minor promotions before getting back in when the UFC bought Strikeforce.

"It’s been a long time coming, and it’s great to get this matchup with Frank," Barnett said.

Barnett deposited Mir roughly on the canvas with a big knee, and the fight was quickly waved off. Mir (16-8) loudly complained the stoppage came too quickly, a complaint echoed by UFC President Dana White on Twitter moments after the fight.

"I actually do feel that it was an early stoppage," Barnett said. "I would always prefer to get the clean finish."

Barnett and Mir both were UFC heavyweight champions for brief periods. Mir has been a UFC mainstay since 2001, but has lost three straight fights since 2011.

Mendes finished off Guida at 30 seconds of the third round with punches, punctuating a strong performance in his fourth consecutive victory.