Rising welterweight standout Brian Norman Jr. continued his ascension up the boxing ladder Thursday with a crushing one-punch knockout.

Brian Norman Jr. retained his WBO welterweight title with a fifth-round knockout of Japan’s Jin Sasaki in Tokyo. Following the defeat, Sasaki was hospitalized and revealed memory loss spanning six weeks.

Brian Norman Jr. knocks Jin Sasaki OUT COLD with a left hook in the first minute of round five. It's an absolutely brutal finish as Sasaki is still lying flat on his back in the ring more than a minute later with members of his team and medical staff huddled around him. There are no celebrations from Norman.