Heavyweight unification series Heavyweight unification series The heavyweight unification series, also known as the Heavyweight World Series, was a sequence of professional boxing matches held in 1986 and 1987 to crown an undisputed champion of the heavyweight class. The series was produced by HBO Sports and promoted by Don King. It ended with Mike Tyson as undisputed champion, holding the championship belts of the International Boxing Federation, World Boxing Association, and World Boxing Council. Prior to the series, the last undisputed heavyweight champion had been Leon Spinks, who won the championship in his 1978 victory over Muhammad Ali. Spinks had been stripped of
AWA World Heavyweight Championship territory. The first champion was Pat O'Connor, who was recognized as the first champion upon the AWA's secession from the NWA as O'Connor held the NWA World Heavyweight Championship as well, which he won on January 9, 1959. The creation of the AWA World Heavyweight Championship along with the NWA World Heavyweight Championship would pave the way for the creation of many other world championships in other wrestling promotions. AWA Wrestling Association and the title became inactive in late 1990 and the organization officially closed down in August 1991 with the title also being decommissioned. The championship is featured in