What should the referee do when a player verbally insults an assistant referee after the game?

When a player verbally insults an assistant referee after the game, the referee should report the incident to the proper authority. This course of action is crucial for addressing unsportsmanlike conduct that occurs outside of the actual match. By reporting the incident, the appropriate authorities—such as the governing body of the league or competition—can take necessary actions, which may include disciplinary measures against the player. This helps maintain the integrity of the sport, upholds respect for officials, and serves as a deterrent against future misconduct.

In contrast, showing a red card is not appropriate in this scenario since the match has already concluded, and red cards are typically issued during play for offenses that warrant ejection. Cautioning the player for unsporting behavior may also be ineffective after the match, as it does not address the matter through formal channels that can lead to more serious consequences. Ignoring the insult undermines the importance of behavior standards expected in sports and allows disrespect to go unchecked. Thus, reporting the incident is the most responsible and appropriate action to take.