On May 19, 1993, 37-year-old Sumbu Kalambay (57-5-1, 33 KOs) and Chris Pyatt fought for the vacant WBO middleweight title.
Kalambay came in to the fight on a 6-fight win streak with a 52% KO rate, and was fighting after a gap of 1 month and 5 days.
Sumbu Kalambay was defending his middleweight titles and, fighting for the middleweight WBO titles against Chris Pyatt and lost via unanimous decision in the 12-round middleweight fight, and adds a loss to his record at 57-6-1.
On April 1, 1991, Sumbu Kalambay and Mike McCallum met again in a rematch.
Kalambay came in to the fight on a 5-fight win streak with a 53% KO rate, and was fighting after a gap of 4 months and 8 days. McCallum was on a 7-fight win streak with a 82% KO rate, and fighting after a layoff of 1 month and 13 days.
Mike McCallum defeated Sumbu Kalambay via split decision in the rematch and successfully defended his WBA middleweight title. McCallum improves his record to 40-1, while Kalambay adds a loss to his record at 51-5-1.
On March 25, 1989, a 32-year-old Sumbu Kalambay (46-3-1, 26 KOs) got a shot at the middleweight IBF title held by 25-year-old American boxer Michael Nunn (32-0, 22 KOs).
Kalambay came in to the fight on a 9-fight win streak with a 52% KO rate, and was fighting after a gap of 4 months and 17 days. Nunn was on a 32-fight win streak with a 68% KO rate, and fighting after a layoff of 4 months and 21 days.
Michael Nunn made quick work of Sumbu Kalambay, stopping the challenger via KO in the 1st. Nunn improves his record to 33-0 (23 KOs), while Kalambay adds a loss to his record at 46-4-1.
On December 19, 1985, a 29-year-old Sumbu Kalambay (37-2-1, 23 KOs) and a 31-year-old Ugandan boxer Ayub Kalule (45-3, 23 KOs) met in the ring in a middleweight bout.
Kalambay came in to the fight on a 3-fight win streak with a 57% KO rate, and was fighting after a gap of 2 months and 23 days. Kalule was on a 5-fight win streak with a 47% KO rate, and fighting after a layoff of 5 months and 29 days.
Ayub Kalule defeated Sumbu Kalambay via split decision in the 12-round middleweight fight. Kalule improves his record to 46-3, while Kalambay adds a loss to his record at 37-3-1.
On April 6, 1985, a 28-year-old Sumbu Kalambay (34-1-1, 23 KOs) and Duane Thomas met in the ring.
Kalambay came in to the fight on a 32-fight win streak with a 63% KO rate, and was fighting after a gap of 29 days.
Sumbu Kalambay lost to Duane Thomas via points decision in the 10-round fight, and adds a loss to his record at 34-2-1.
On December 5, 1980, a 24-year-old Sumbu Kalambay (2-0, 2 KOs) and Aldo Buzzetti met in the ring.
Kalambay came in to the fight on a 2-fight win streak with a 100% KO rate, and was fighting after a gap of 1 month and 11 days.
Sumbu Kalambay lost to Aldo Buzzetti via points decision in the 8-round fight, and adds a loss to his record at 2-1.