Floyd "Pretty Boy" Mayweather Jr., stepping into the ring for the first time in his career as a welterweight, scored a sixth-round knockout of Sharmba Mitchell in a non-title bout Saturday night at the Rose Garden. One of the best pound-for-pound boxers, Mayweather dominated the bout, flooring Mitchell with a solid right hand in the third round. Mayweather continued to pound away with lightning-quick punches in the fourth. Mitchell finally succumbed after he was driven to one knee following a solid body shot from Mayweather in the sixth. The punch landed just below Mitchell's ribs and he was counted out at the 2:05 mark of the round by referee Richard Steele. The 28-year-old Mayweather (35-0, 24 KOs), who was coming off a sixth-round TKO of Arturo Gatti in June in the WBC light welterweight bout, stepped up in weight for Saturday's bout, but was clearly dominant, connecting on nearly three times as many punches as his opponent. Next up for Mayweather could be a fight against undisputed welterweight title holder Zab Judah. He could also ask for a bout against Shane Mosley or Winky Wright. Mitchell (56-5), a former champion at the 140-pound level, has lost two of his last three bouts. The 35-year-old also fell to Kostya Tszyu in a fight for the IBF light welterweight crown on November 6, 2004.