The incident happened at around 10.35pm on Saturday, October 9, on High Common Road in East Kilbride.
Two men, aged 35 and 44, were assaulted by a group of men in what Police Scotland has described as an ‘unprovoked attack’.
The 35-year-old victim was taken to Wishaw General Hospital where he was treated for serious, non-life threatening injuries.
One of the suspects is described as 30-40 years old, 6ft 2in tall and bald.
Detective Constable Ashley Hind, of Lanarkshire CID, said: “This was a serious assault and we are keen to trace those responsible as soon as possible.
“I would urge anyone who may have been in the area at the time and saw the incident to contact police as soon as possible.”
Anyone with information is asked to contact police on 101, quoting incident 4024 of 9 October, or alternatively call Crimestoppers anonymously on 0800 555 111.