The 16 year old received facial injuries in the attack, including a shattered cheekbone, dislocated nose and a rip to the back of one eye which may result in a permanent loss of vision, as well as other serious injuries.
Detective Inspector Richard Thornton said: “We are appealing to anyone who may have witnessed this incident, which we believed happened after the concert around midnight, as this young man and his girlfriend were making their way to the Boucher Road to board their bus home.
“We would like to talk to a white male in his late teens who was seen standing on the steps of a white bus, wearing denim shorts and no top.
“He is described as having short dark hair, of average build and height and had a northern Irish accent.
“It is reported that following a verbal exchange, this male kicked and punched the 16 year old in the face, before another four men got out of the bus and became involved in the assault.
“Anyone who has information that could help us with our investigation should get in touch with detectives at Musgrave on the non-emergency police number 101, quoting reference number 1262 of 29/8/17.
“Alternatively, information can also be given anonymously through the independent charity Crimestoppers on 0800 555 111.”