Dubbed the Nigerian Nightmare, he scored a second-round knockout to finish American Jorge Masvidal on Saturday.
It secures his undisputed UFC welterweight title.
The bout exploded in round two with Masvidal sent crashing.
But Usman says his work is not over yet.
But he says his fight now is to continue improving his game.
"I've finished really my last three opponents, I've finished them all. So right now I just need to take some time and continue to train and get better, but these guys got to show me something because right now, I'm the champion, I'm the most active guy in the division, these guys just can't wait around and wait for me to call their number, they need to show me something," he said.