WASHINGTON (AFP) - Britain's Amir Khan tipped the scales at 139 pounds, one pound less than US rival Lamont Peterson during Friday's weigh-in on the eve of their light-welterweight world title bout. England's Khan, 26-1 with 18 knockouts, defends his World Boxing Association and International Boxing Federation crowns and an eight-fight winning streak against Peterson, 29-1-1 with 15 knockouts. One day after his 25th birthday, the fighter from Bolton, in northern England, looked fit as he weighed in one pound lighter than his career heaviest from July for his fifth-round knockout victory over American Zab Judah. Peterson was a half-pound heavier than his last fight, a 12th-round knockout of Victor Cayo in July, and a pound lighter than his draw with US rival Victor Ortiz last December.