A disgruntled patron who was kicked out of a club in Sydney's southwest allegedly stabbed a man who was trying to help a security guard.
The victim was stabbed in his chest and side outside the Revesby Workers' Club shortly before 4am on Wednesday, NSW Police said in a statement.
Police were told the conflict was sparked when the man who was excluded from the club returned and allegedly threatened the security guard with a knife.
The man who tried to intervene to help the guard was stabbed twice before the armed man was wrestled to the ground and held until police arrived.
"A 73-year-old man has been taken to Bankstown Police Station where inquiries are now under way into the incident by detectives," police said.
The injured man was treated by paramedics before being taken to Liverpool Hospital in a serious but stable condition.
