After Durelle retired from boxing he got involved with wrestling as both a competitor and a referee.
I recall being at a match back at the old Halifax Forum about 40 years ago. Yvon was wrestling some guy whose name I have long forgotten. Durelle was not doing very good but suddenly there was a "CRACK" as a right cross decked the guy laying him out cold in the middle of the ring. I remember exclaiming to my friend that there was nothing fake about that hit. The guy was down and out!
About twenty years later I got to know one of the men promoting those matches and I asked him if he remembered the incident? He told me that this had happened three times. He said that between the ring setting and the roar of the crowd Yvon would forget where he was and instinct would take over. When that happened the lights went out very quickly for somebody.