Gang Crime Squad detectives have charged a 30-year-old man over an alleged one-punch attack outside a Mandurah pub.
It happened around 10pm on Friday at the Monkey Bar and Lounge on Pinjarra Road.
Police will allege during an altercation the accused punched a 36-year-old man causing him to fall to the ground.
The victim was rushed to Royal Perth Hospital with serious injuries.
A Mandurah man will appear in the Perth Magistrates Court on Thursday charged with grievous bodily harm.