About 5.35am, police received reports of a disturbance outside a licensed premises near the intersection of James Street and Mountain Terrace.
Emergency services, including St John WA, attended the scene and located a 36-year-old man who had been assaulted, fallen, and struck his head on the pavement, losing consciousness. He was conveyed under priority conditions to Royal Perth Hospital for treatment of serious, life-threatening injuries and remains in a critical condition.
A 20-year-old man is currently assisting police with inquiries.
Anyone who witnessed the incident or has mobile phone, CCTV or dash-cam footage from the area at the time is urged to contact Crime Stoppers online at www.crimestopperswa.com.au or call 1800 333 000.
Reports to Crime Stoppers can be made anonymously.
