Shakur Stevenson became a unified super featherweight champion on Saturday night after dominating Oscar Valdez in a unanimous decision victory to add the Mexican's WBC title to his WBO belt. Stevenson improved to 18-0 as he handed Valdez his first defeat in 31 professional fights, with two of the three ringside judges scoring the bout 118-109 and the third 117-110 for the American. Stevenson sent Valdez to the canvas with a left to the head in the sixth round on the way to his first defence of the WBO title he won with a 10th-round technical knockout of Jamel Herring in October. Valdez upset Miguel Berchelt last year to win the WBC title and retained it with a unanimous decision over Robson Conceicao in September. The 31-year-old Mexican, a two-time Olympian, was embroiled in controversy when the bout against Conceicao was allowed to go ahead after he tested positive for the banned stimulant phentermine eight days before the fight. Valdez blamed the positive result on herbal tea and authorities ruled the drug was prohibited only during competition. "He is a tough champion, but I prepared to beat him," Stevenson said in an in-ring interview. "I'm ready for anyone, I want all the belts." But Stevenson had personal business to attend to immediately after the fight. He dropped to one knee in the ring to propose to his girlfriend, rapper Young Lyric, who said yes. The couple have a baby daughter. Valdez acknowledged that Stevenson was the better fighter on the night. "He has a very great boxing quality and today he was the best in the ring," Valdez said. "He moves very well, he's a champion. He has speed, he's a great boxer."