The primary function of a referee in sports is to enforce the rules of the game and ensure fair play. Referees make critical decisions regarding fouls, violations, and scoring, acting as impartial officials who maintain the integrity of the sport. They are responsible for managing the flow of the match, intervening when necessary, and communicating with players and coaches. A referee's authority and judgment are essential for preserving order and upholding the spirit of competition within any sporting event.