After Cassius Clay changed his name to Muhammad Ali, he defended his heavyweight boxing title for the first time in May, 1965, against which opponent?

The May 1965 bout was a highly anticipated rematch. Just over a year earlier, a brash young challenger then known as Cassius Clay had shocked the world by defeating the intimidating heavyweight champion, Sonny Liston. Shortly after that stunning victory, Clay publicly announced his conversion to the Nation of Islam and changed his name. Thus, when he stepped back into the ring to face Liston in Lewiston, Maine, it was the first time he defended his world title as Muhammad Ali.

The fight itself became one of the most controversial and iconic events in sports history. Less than two minutes into the first round, Ali dropped Liston with a quick, short right hand that many in the audience failed to see, a blow later nicknamed the "phantom punch." The ensuing chaos, with Ali standing over his fallen rival and yelling "Get up and fight, sucker!", was captured in one of the most famous photographs of the 20th century. The swift and bewildering knockout cemented the end of the Liston era and dramatically launched the championship reign of Muhammad Ali.