08/17/2013 11:10 EDT | Updated 10/17/2013 05:12 EDT

Chael Sonnen submits Shogun Rua in first round at UFC Fight Night 27

BOSTON - Chael Sonnen (29-13-1) did exactly what everyone expected him to do: He outwrestled Mauricio "Shogun" Rua (21-8). Then he did what was almost unthinkable. He submitted the former UFC light heavyweight champion in the first round.

The bout served as the main event of Saturday's "UFC Fight Night 26: Shogun vs. Sonnen" card at Boston's TD Garden.

Sonnen, who is primarily a middleweight, took Rua down immediately at the opening bell. But Rua patiently worked back to his feet and actually scored his own trip, working briefly from top position. But he couldn't hold Sonnen down, and he'd soon pay for the mistake.

With both fighters back on their feet, Sonnen shocked Rua by latching in a guillotine choke and falling to his back to finish the hold. With time ticking down, Sonnen squeezed the neck. Rua held out for as long as possible but was forced to tap with 13 seconds left in the first round. It was Rua's first submission loss since 2007.

Afterward, Sonnen took the mike and issued a formal challenge to Brazilian MMA legend Wanderlei Silva.

"Right here on the UFC's new home, FOX Sports 1, Wanderlei Silva, 6-feet tall and 205 pounds," Sonnen said in his post-fight interview. "Boy until I met you, I didn't know they could stack crap that high."

The night's co-feature saw heavyweight dark horse Travis Browne (15-1-1) earn a stunning, come-from-behind victory over former Strikeforce champion Alistair Overeem (36-13).

Browne was in trouble early, as an aggressive Overeem tagged him with several crushing knees to the body. While Browne absorbed the first few blows, the damage eventually sent him crumpling to the floor, where Overeem unleashed a flurry of vicious right hands. Browne covered up and moved each time referee Mario Yamasaki warned him the fight was about to be called, and he eventually found a way to his feet. Once there, things changed.

As Overeem walked forward, Browne continually kicked from range. Eventually, a front kick found Overeem's chin, sending him toppling to the canvas. Browne followed with two massive hammerfists, and Yamasaki awarded him the knockout win at 4:08 of the first frame.

"We didn't know I was going to get my butt kicked for the first few minutes, but everything else went like we thought it would," Browne said. "I was mentally there, but I've never had my body shut down like that on me. The referee kept saying he was going to stop it, and I was telling him that I was OK.

"I was thinking about my sons and providing for my family; this is what I'm made of."

In a key bantamweight contest, former World Extreme Cagefighting champion Urijah Faber (29-6) proved he's still one of the world's absolute best 135-pounders with a convincing decision win over Brazilian contender Iuri Alcantara (27-5).

It was Alcantara who looked best early, cracking Faber's chin with a strike he later admitted he though may have broken his jaw. A lateral drop shortly after saw Alcantara secure a dominant position on the floor, where he went to work looking for a submission. Faber somehow survived each attempt and actually swept to the top, where he claimed momentum for the remainder of the fight.

Faber outwrestled Alcantara for the final to-and-a-half rounds, repeatedly taking the action to the floor and preventing any counter attacks while peppering the head and body with ground-and-pound blows. After 15 minutes, Faber was awarded a decision win, 30-26, 30-26 and 30-27.

"The beginning of the fight was pretty intense, and he was catching me with some really big punches," Faber said after the fight. "Lots of respect for Iuri. He's a tough guy, and it was a great fight."

In a matchup of perennially underrated welterweight contenders, Matt Brown (20-11) earned his sixth consecutive victory with a stunning 29-second knockout win over friend and former training partner Mike Pyle (25-9-1).

Brown pushed forward from the opening bell, firing punches with impressive pressure. As Brown flurried, a right hand wobbled Pyle before a knee sent him to the canvas. Brown pounced with big right hands on the floor, and referee Kevin MacDonald stepped in to wave off the fight less than a half-minute after it started.

"I really didn't want to do that," Brown said after the fight. "I love Pyle. He's a great guy and a friend, but once you're in there, it's either you or me.

In a middleweight action, Boston native and late replacement John Howard (21-8) pulled off an upset win over "The Ultimate Fighter 17" finalist Uriah Hall (8-4).

Hall, a striking wizard, surprisingly seemed content to wrestle for most of the fight, but Howard proved up to the challenge, defending well against the cage and countering with chopping leg kicks and leaping left hands. Hall unleashed flashy techniques in spurts, but none landed flush, and he failed to push forward after the missed techniques. Meanwhile, Howard turned in a blue-collar effort, outworking his opponent just enough to earn a split-decision in a bout that failed to live up to its potential.

Final scores were 30-27, 28-29 and 29-28, allowing Howard to pick up the win in his first UFC fight since June 2011.

"He did surprise me with the takedowns, and he's very dynamic on his feet," Howard said after the win. "Fighting in my hometown of Boston is a dream come true for me, and I'm so thankful to the UFC for bringing me back."

In the night's first main-card matchup, Boston native Joe Lauzon (22-9) struggled to find any success against fellow lightweight Michael Johnson (14-8) and fell victim to a one-sided unanimous-decision.

Johnson controlled the action from start to finish, repeatedly lacing a straight left hand to the chin and countering every Lauzon strike with a flurry of his own. A gutsy Lauzon never stopped walking forward, but he struggled to gain any momentum, and Johnson was awarded the win with scores of 30-27, 30-27 and 30-25.

"This was definitely my best performance, not just because of how I performed but who I performed against," Johnson said after the win. "Joe is one of the guys I respected and wanted to fight from the time I got into the UFC. I knew he'd be willing to compete with me where the fight was tough. He brought out the best in me."