At about 12.05 am that morning, the 19-year-old was walking with his girlfriend in the High Street, near the Santander Bank, when he was approached by a man who began assaulting him.
The victim was knocked to the ground and suffered bruising following a number of punches being thrown. His girlfriend attempted to separate the two and in doing so dropped her mobile phone, which was then picked up by the assailant, who made off from the scene with it.
Police are investigating and have issued a description of the attacker.
Constable Fiona Sword said: “The man we want to trace is described as being in his early 20s, about 5’10” tall, with short shaven hair and some facial hair and was wearing a black Polo Ralph Lauren puffed jacket, dark jeans and dark trainers.
“This appears to have been an unprovoked attack by this man, who then made off with a mobile phone when the opportunity arose. The victim was not seriously injured but was left shocked at the incident.”
Anyone who may have witnessed this incident, or who can help identify the man, is asked to call Dumfries on the 101 number, quoting reference PDG 0044920318.