The Forum, Inglewood, California - Making his American debut, Olympic gold medal winner Oleksandr Usyk (11-0, 10KOs) scored three knockdowns to stop Thabiso Mchunu (17-3, 11KOs) in the ninth round to retain his WBO cruiserweight championship for the first time.

The battle of southpaws began with Usyk working his jab and sizing up Mchunu, who was using his short stature to make things very tough for Usyk. The second round was more of Usyk jabbing, with Mchunu landing the bigger and more effective shots.

Usyk began to get more active in the third, but it was still Mchunu landing the better shots with his right hand finding the mark. Usyk picked up the pace even further in the fourth, by letting his hands go and started letting go with some very big punches.

Uysk was more accurate in the fifth, and began to find the target more often and was really unleashing with his punch ratio. Mchunu was landing a good shot here and there but not nearly active enough.

The sixth saw Usyk really unloading and landing some very hard shots on Mchunu, and a big left uppercut sent him. Mchunu got up and Usyk went right after him to to follow-up, but the Mchunu managed to fight him off to get away from trouble. Mchunu was trying to re-establish himself in the seventh while Usyk took his foot off the gas. Towards the end of that round, Mchunu was getting overwhelmed by a lot of shots coming at him.

Usyk went right back to work in the eight, landing some good punches but then he seemed to get bothered by a few hard right hands that countered back from Mchunu. For some reason Mchunu did not follow up with anything to see if Usyk was actually hurt.

Usyk started landing to the body in the ninth and then following up with combinations to the head. A few more punches wore Mchunu down for a second knockdown. Then Usyk jumped on with Mchunu trying to fight him off, but Usyk continued to land hard shots and sent him down for a third time - and the referee waved off the fight.