A couple have been injured in their home in Sheffield in what police say appears to be a motiveless attack.
The 18-year-old man and the woman, aged 20, were watching television at about 2200 BST on Saturday when a group of four or five men called at the door.
They then forced their way into the flat in Piper Road, Longley.
In the scuffle that followed, the man was knocked unconscious and was stabbed in the calf and buttocks. The woman received minor injuries.
Both were taken to the Northern General Hospital where they were released after treatment.