The gang of knife and bottle wielding thugs attacked the men early yesterday in South Lanarkshire.
Both victims, aged 22, are being treated in hospital after they were assaulted by a group of up to six men while walking with friends in Cruachan Road, Rutherglen, at 2.35am, yesterday.
The gang challenged the men to a fight, before attacking one with a knife and the other with a bottle.
They were taken to the Victoria Infirmary and the Glasgow Royal Infirmary where they are being treated for their injuries.
Hospital staff describe their condition as serious but stable.
The road was closed while investigations were carried out.
Police are checking CCTV in the area and appealing for anyone with information about the attackers to come forward.
The suspects are described as being in their early 20s, wearing dark tracksuits or similar clothing.
Detective Sergeant Josie McGhee, of Rutherglen CID, said: "This would appear to be a totally unprovoked attack. From our enquiries we are aware that the group of men responsible may already have challenged others in the area to a fight.
Anyone with information is should contact police at Rutherglen Police Office on 0141 532 5200 or Crimestoppers on 0800 555 111, where details can be given in confidence.