District native Lamont Peterson pulled off one of the more stunning upsets in recent boxing memory, winning a split decision over Amir Khan in their unified super lightweight title bout on Saturday night at the Walter E. Washington Convention Center.

So sure of his ability in the boxing ring, Khan traveled to the home town of his challenger expecting a tidy victory in defense of his titles. The bold move backfired, though, when to the delight of the partisan crowd of 8,647, Peterson clearly wasn’t willing to be just another glorified sparring partner in the first major championship fight in the nation’s capital since 1993.

Virginia-based referee Joseph Cooper deducted a point from Khan in the seventh and 12th rounds for pushing off. They proved decisive in a fight that came down to a razor-thin margin.

Nelson Vasquez scored the fight 115-110 to Khan, but fellow judges George Hill and Valerie Dorsett each gave the fight to Peterson, 113-112.

“I’m not the kind of guy who falls for anything. I stand for something,” said Peterson, who ran his record to 30-1-1. “A lot of people looked at me as an underdog in this fight. They never gave me a chance to win.”

Khan (26-2, 18 knockouts) disputed the decision, saying between Peterson and the deductions by Cooper “it was like I was against two people in there.” He added: “I’m ready for a rematch. I’m here, and I’ll take it. This is why boxing hasn’t been in D.C. for 20 years because you get a decision like this.”

When Khan knocked down Peterson in the first round, the former champion appeared the superior fighter by a long shot and well on his way to an easy win. Peterson, however, withstood the early barrage and countered with combinations that had Khan retreating at times. Peterson landed one such offensive in the sixth, forcing Khan into the ropes while covering up in self-defense.

“I followed my game plan,” Peterson said. “It’s a 12-round fight, not a three-round fight. I didn’t get worried when I got knocked down in the first round.”

Then in the seventh, Peterson was at it again. The pluck of his underdog opponent confounded Khan to the point that the referee pulled the fighters apart before announcing the point deduction. Finally, in the 12th, Peterson got the crowd into the fight one last time, and he advanced repeatedly to chants of “D.C., D.C., D.C.” that only grew as the judges’ results were revealed.

“He kept trying to pick me up, and he was wild,” Khan said. “He was coming with his head lower and lower every time. I had to push him away because I was trying to stay away from his head. It was so low. He was being effective in pressuring, and I was the cleaner fighter all night.”

The victory continued a storybook ascent for Peterson, who became the IBF’s top contender after overcoming poverty and homelessness as a youth on the streets of the District. Not only did Peterson show he belongs in the same circles as the British champion, but he now is positioned to enter the conversation perhaps among the top pound-for-pound fighters.

In the co-main event, Seth Mitchell continued his ascent in the heavyweight ranks in overpowering fashion, connecting with a resounding left hook in the second round and continuing his assault on Timur Ibragimov until the fight was stopped at 2 minutes 48 seconds.

Mitchell’s ninth consecutive victory by knockout kept the Brandywine native unbeaten and still the best hope for an American champion in boxing’s most glamorous division, which the Klitschko brothers have ruled for the past half dozen years. Wladimir Klitschko is the WBA, IBF and WBO titleholder, and Vitali wears the WBC belt, but Mitchell has stated his intention of dethroning either or both.

With performances such as this, Mitchell (24-0-1, 18 KOs) just may get his wish. After a first round in which he measured his Uzbek opponent, Mitchell unloaded with a left hand early in the second that wobbled Ibragimov (31-4-1). Shortly thereafter, Mitchell delivered repeated blows with his right and eventually backed up Ibragimov into a neutral corner.

That’s when Mitchell continued to hammer away until the referee ceased the proceedings. That triggered wild applause from the partisan crowd that came to support the hometown boxer whose last fight in the District was on April 2, 2010, also at the convention center.

“I’m blessed with natural athletic ability,” Mitchell said. “I have the size, power and speed, but I don’t that that for granted, and I work really hard. This is the platform I want to be on. I want to continue the buzz.”

Mitchell’s rise in the heavyweight ranks has been as unusual as it has been rapid. A football star in high school at Gwynn Park, Mitchell was named All-Met Defensive Player of the Year and parlayed that acclaim into a scholarship at Michigan State. There, he sprained his right knee and missed his freshman season.

After playing in just five games as a sophomore, Mitchell spent a chunk of the next season recovering from knee surgery. It was during that time he realized football wasn’t going to be in his future once he left school with a degree in criminal justice.

Later, Mitchell happened to catch the professional boxing debut of Tom Zbikowski, who played safety for Notre Dame and in the NFL for the Baltimore Ravens. After a handful of amateur bouts, Mitchell turned pro in 2008, and he since has been climbing the division.