The decision drew criticism from promoter Bob Arum, who said Leonard was risking everything by facing the undefeated Kalule before taking on the tough Hearns fight. Arum publicly predicted that Kalule would win and warned that an upset would seriously damage the interest of the Leonard-Hearns tournament.
Kalule was not a local representative. The Ugandan-born southpaw, who is based in Denmark, comes in with an overall record of 36-0 and holds both the WBA and The Ring light middleweight championships.
Kalule entered the fight with a perfect record of 36-0 and had never been defeated or stopped. The Ugandan-born southpaw, who fought in Denmark, holds the WBA and The Ring light middleweight belts and is considered one of the top fighters in the division, although Leonard entered as a heavy favorite.
The event also featured the WBA welterweight champion, Thomas Hearns, defending his title against Pablo Baez in the main event. The fight was scheduled to be a 10-round fight, but Hearns and trainer Emanuel Steward pleaded with promoter Bob Arum to make it a defense of the championship. Arum also agreed to give Hearns equal pay with Leonard in promotional posters, although Leonard remained the main event.
From the opening bell, Leonard surprised many viewers by abandoning his trademark stick-and-move style. Instead, he stood his ground, pumping a hard jab, throwing quick combinations, and repeatedly hitting Kalule with high hand speed.
Leonard dominated the first six rounds, but the undefeated champion showed why he has reached the top of the division. In the seventh, Kalule landed a short right hand that stunned Leonard briefly and breathed new life into the contest. The eighth was contested as both soldiers punched each other, Kalule continuing to push forward.
This battle ended in the ninth round.
Towards the end of the round, Leonard landed a hard right hand that hurt Kalule. When the champion tried to bend the horn, Leonard unleashed a combination of three punches that made Kalule fall on his back. Although Kalule got up before the count ended, he informed referee Carlos Berrocal that he was unable to continue, awarding Leonard the technical victory in the ninth round.
The win improved Leonard's record to 30-1 and made him a two-division world champion by capturing the WBA and The Ring light middleweight titles. More importantly, it removed any doubts about his ability to compete effectively against naturally bigger opponents.
Three months later, Leonard built on that momentum in his historic welterweight unification fight against Thomas Hearns in Las Vegas. Their September 1981 bout became one of the defining fights of boxing's golden era, with Leonard fighting for a stunning 14th round stoppage after trailing on points.
For Kalule, the loss ended their 36-game unbeaten streak. Although he continued boxing for several years, he never again reached the same level of prominence or won a world championship.
Although the “Astrowars” are often overshadowed by Leonard's rivals Duran, Hearns, Marvin Hagler and Wilfred Benítez, it remains one of the most important milestones of his career. It proved that Leonard could conquer the second weight class, defeating the undefeated world champion of his time, and served as the last step before boxing's most famous victory.
