Who did Muhammad Ali defeat to win his first heavyweight world title?

Muhammad Ali defeated Sonny Liston to win his first heavyweight world title. The fight took place on February 25, 1964, in Miami Beach, Florida, when Ali was still publicly known as Cassius Clay.

Liston entered as the heavily favored champion and was widely considered one of boxing's most intimidating heavyweights. Clay, an outspoken 22-year-old challenger, used speed, footwork, and a sharp jab to frustrate him. Liston did not answer the bell for the seventh round, giving Clay a technical-knockout victory and one of boxing's biggest upsets.

The result also marked a major transition in Ali's life. Soon after the fight, he announced his association with the Nation of Islam and adopted the name Muhammad Ali. The two men fought again in 1965, when Ali won by a controversial first-round knockout often called the phantom punch. That rematch did not decide the original title victory: Liston was the champion Ali defeated in 1964.