The incident, in the Castlemilk area of Glasgow, took place at around 11.25pm on Friday when a group of teenagers, who were in a playpark near to Machrie Drive, were approached by the men.
One of the teenagers, an 18-year-old man, was chased and attacked by the men. He was later taken to Hairmyres Hospital in East Kilbride for treatment.
Medical staff have described his condition as stable.
Detective Sergeant Keith Runcie said: "This attack, which we are treating as attempted murder, has left this young man with very serious injuries.
"We believe that the 18 year-old man was the intended target and our officers are currently checking CCTV in the local area as well as making door-to-door inquiries to try and establish exactly what happened here.
"Where were you last night? There are lots of houses which back on to the park from Ballantay Road and Machrie Drive. Did you hear or see anything?
"Somebody will know something about this attack and we urge you to come forward with this information so we can trace those responsible."