The man was punched in the face at Harwich and Parkeston Football Club, in Main Road, Harwich, at around 1am on Sunday, June 23.
The attack followed a disturbance at the clubhouse after a man became aggressive to staff when he was asked to leave the building.
The man became threatening, with three people in total being assaulted.
Officers arrested a 19-year-old man from Harwich on suspicion of grievous bodily harm with intent, actual bodily harm and common assault.
He has been released on bail until Wednesday, July 31.
Anyone with information is asked to call Clacton CID on 101 quoting crime reference 42/102511/19 or Crimestoppers anonymously on 0800 555 111.
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