Abdulrahman Yafooz, aged 20, of Morgan Road, Shirecliffe, was sentenced at Sheffield Crown Court yesterday, after being charged with the robbery which took placeÂ in the Ecclesall Road area on May 10.
The victim, an 18-year-old man, was walking home after leaving friends in Endcliffe Park when he was followed by a group of youths, which included Yafooz.
Just past the entrance of Frog Walk he was pushed into a doorway, and threatened with what officers have described as a hunting style knife.
Detective Constable John Briers, the investigating officer, said: 'The victim was then dragged along the walk, whilst being repeatedly punched in the face.
'It was a violent and nasty attack, which lead to the victim handing over his phone and wallet. Thankfully, a passing motorist noticed what was happening and sounded his horn, distracting the group and allowing the victim to break free from his attackers.
'We managed to trace Yafooz by tracking the stolen phone.
'The incident was extremely distressing for the victim and I am pleased that Yafooz has been handed a significant sentence for his actions that night.'