June 6 (Reuters) - A 43-year-old man was convicted on Thursday of head-butting former Manchester United captain Roy Keane following a Premier League match.

Scott Law, who British media reports said was an Arsenal fan, was found guilty of assault following a trial at Highbury Magistrates' Court. The incident took place on Sept. 3 last year after Arsenal's 3-1 win over United at the Emirates.

The Sky Sports pundit was forcefully head butted near doors at the Emirates while on his way to complete the match analysis after a United goal was disallowed towards the end of the game. Keane suffered further bruising to his left arm.

"This gratuitous and senseless act of violence was completely unacceptable," Kevin Christie, Crown Prosecution Service London North Football Lead Prosecutor, said on Thursday.

"When anyone attends a football match, either to work or to support a team, they should be able to feel safe and secure in that environment.

"The Crown Prosecution Service works in close partnership with the police to ensure that all perpetrators of violence at football grounds are brought to justice."

The defence team accused Keane of elbowing Law in the face, citing CCTV footage from inside the stadium.

However, the Metropolitan Police's Detective Constable Phil Dickinson, who was in charge of the case, said: "There may have been contact, but it does not look like a deliberate elbow to the face in my opinion."