Mandurah Detectives are investigating an alleged one-punch assault at the Monkey Bar and Lounge overnight.
It's understood around 10pm, a physical altercation occurred between a group of people outside the licensed venue on Pinjarra Road.
Police said during this time the 36-year-old man was punched by another man which caused him to fall to the ground.
The victim allegedly received serious injuries as a result of the incident and was treated by St John Ambulance at the scene.
He was then conveyed to the Intensive Care Unit at Royal Perth Hospital.
The other man fled the scene before police arrived.
Detectives are appealing for anyone who witnessed the incident, or with information regarding this incident, to contact Crime Stoppers by calling 1800 333 000 or by making a report online at www.crimestopperswa.com.au
Man charged after Rockingham Shopping Centre incident
Concerns for missing West Pinjarra teen
Scorching Christmas temperatures for Perth, Rockingham, Mandurah
Teen charged over Baldivis arson attack
Concerns for missing boy last seen in Warnbro
Baldivis Sports Complex officially complete with unveiling of final stage
Teen dies at Logue Brook Dam
Mandurah named WA’s Most Accessible Community
Police attend separate crashes in Lakelands and Port Kennedy