In a major upset, Robbie Lawler knocked out Josh Koscheck in the UFC 157 pay-per-view opener.
Lawler hadn't competed in the UFC since 2004, and his opponent Koscheck, a former UFC welterweight top contender, was near a 4-to-1 favorite.
More Coverage: UFC 157 Results | UFC news
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Koscheck controlled the bout early with his wrestling but the fight's complexion changed when Lawler got back to his feet and landed a knee to the face. He swarmed Koscheck with a barrage of rights. Koscheck went down and Lawler continued the assault until referee Herb Dean stepped in with 3:57 left in the first round.
Koscheck immediately protested the stoppage, but to no avail.
"I was raining down hard shots and he was going to take a beating," Lawler said. "He wasn't coming back."
It was Lawler's first time at welterweight since an April 2004 loss to Nick Diaz, and his first time in the octagon since losing to Evan Tanner in October 2004.
Lawler is now 20-9 with 1 no contest.
Koscheck, who hadn't fought since last May, has now dropped two in a row, falling to 17-7.