Michael Nunn vs Sumbu Kalambay

On Saturday, 25th March 1989 at the Hilton Hotel, Las Vegas, Nevada, Michael Nunn made the second defense of his IBF World Middleweight Title against Sumbu Kalambay. Promoted by Top Rank, the fight was aired on HBO World Championship Boxing and saw Michael Nunn, with a record of 32-0-0, facing Sumbu Kalambay, who held a record of 46-3-1. Nunn was the 5 to 1 favorite going into the fight, which was initially scheduled as a unification match between the IBF champion Nunn and the WBA champion Kalambay.

However, the WBA stripped Kalambay of his title for choosing to fight Nunn instead of the WBA's mandatory challenger, Herol Graham, whom Kalambay had defeated two years prior. This decision left the IBF World Middleweight Title as the sole title on the line for this bout.

The disparity in height and reach between the two fighters was evident, with Nunn standing at 6-foot-1 and possessing a 77-inch reach advantage, while Kalambay stood at 5-foot-9. Despite the physical differences, no one could have anticipated the outcome of the fight.

In a stunning turn of events, Michael Nunn defeated Sumbu Kalambay by knockout at just 1:28 in the first round. Referee Richard Steele officiated the match. Nunn's victory came from a one-punch knockout, a powerful left to the chin of Kalambay. This knockout marked the only such loss in Kalambay's career.

Both fighters received a significant payday for their participation in the event. Nunn took home a purse of $1.1 million, while Kalambay earned $400,000. The fight's decisive conclusion garnered attention, leading The Ring magazine to name it the Knockout of the Year.