Michael Nunn vs. Sumbu Kalambay, billed as Premier Battle, was a professional boxing match contested on March 25, 1989, for the IBF middleweight title.

[6] These plans were derailed almost immediately when the WBA refused to sanction the Nunn–Kalambay fight, instead mandating that Kalambay face their number-one ranked contender Herol Graham, though Kalambay decided to go through with facing Nunn leading to the WBA to strip him of their title.

[8] At the insistence of Arum, Kalambay was still introduced as the WBA middleweight champion by announcer Michael Buffer during the pre-fight introductions.

Kalambay, not largely known in the United States and seven years older than Nunn, was installed as a 4–1 underdog by oddsmakers.

Kalambay hardly made an attempt to get back up as he was counted out by the referee, giving Nunn the knockout victory after only 1:28 of action.