Michael Spinks turned professional with a win over Eddie Benson, knocked out in one round on April 17, 1977 in Las Vegas. With that, Spinks began a 31 fight winning streak that would almost extend to the end of his career. After four more wins, Spinks finished '77 with the first fight that began a gradual ascent in opposition quality: an eight-round decision over Gary Summerhays, a popular young boxer of the time. In 1978, Spinks won two fights, including an eight-round decision over former world Middleweight title challenger Tom Bethea, in the same undercard where his brother Leon dethroned Ali as
Leon Spinks vs. Muhammad Ali II holding. The Associated Press scored the fight 12-3 for Ali, while the three judges had the bout 11-4, 10-4 and 10-4 all in favor of Ali giving him a Unanimous decision win. Ali regained the WBA heavyweight title and avenged his split decision loss to Spinks from seven months prior. He also became the first man to win the World Heavyweight Championship three times. In June 1979, Ali sent an official letter of retirement to the WBA. Promoter Bob Arum said he paid Ali $300,000 to announce his retirement because Ali's reluctance had delayed the scheduling of a fight between