Promoted as "The Showdown," Leonard (30-1 with 21 KO) fought Hearns (32-0 with 30 KO) on September 16, 1981 at Caesars Palace in Las Vegas, Nevada to unify the World Welterweight Championship in a scheduled fifteen-rounder. They fought before a live crowd of 23,618 and a worldwide TV audience of some 300 million.