Police said he was taken to hospital after the "serious assault" which happened at Wauchope Court some time between 03.45 and 05.45 GMT on Sunday.
Det Sgt Michael Hawthorne said it was believed the victim attended a house party in the area before the attack.
He appealed to anyone who was at the party or who witnessed the assault to contact detectives.
A man in his 20s has been beaten up after he attended a house party in south Belfast on New Year's Eve.