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Referee Joe Cortez calls time after Victor Ortiz, top right, head butted Floyd Mayweather in the fourth round during a WBC welterweight title fight, Saturday, Sept. 17, 2011, in Las Vegas. Mayweather won by knockout in the fourth round. (AP Photo/Eric Jamison)


Floyd Mayweather Jr. and Victor Ortiz fought at the MGM Grand in Las Vegas.