His son was sent off the field after being given a yellow card by the 15-year-old referee, the court heard.
After the match, Selifino approached the referee asking for the reason behind the decision before calling him "hopeless".
Selifino then rushed towards him, grabbing him with both hands, in an physical altercation that left welt marks above the teenager's shoulder as well as a graze on his chin.
Members of the public rushed in and pulled the parties apart.
To his credit the 15-year-old went straight out to referee again after the incident, Judge Harvey said.
He was understandably upset and shocked by what happened, later experiencing anxiety, he said.
Selifino pleaded guilty to assault at his first court appearance.
Judge Harvey said it must be made clear "there will be consequences" for this type of behaviour which interfered with recreational activities of young people.
He sentenced Selifino to 100 hours of community work and ordered him to pay $1000 to the victim.
Selifino's lawyer Peter Choi argued for continued and permanent name suppression, on the basis of mental health concerns.
This was opposed by the New Zealand Herald and police.
Feelings of guilt and embarrassment have been mentioned by a representative of the New Zealand Herald as a "natural consequence" of being in court for offending, said Judge Harvey, before declining the application.