Fuerza Pública officers said they detained 70 persons mostly for disturbances connected to the soccer game Sunday at Estadio Nacional.
All the arrests came outside the stadium and some were well away in the nearby Parque la Sabana.
Police have an advantage now with a new law that is designed to prevent violence at soccer games. The police are up against the barras, the unruly fan groups, in this case supporting the Liga Deportiva Alajuelense or Deportivo Saprissa.
The confrontations began at 9:30 when a youngster smacked a horse of the police mounted detachment. The horse bolted and threw the rider, who required medical attention, said police.
Officers detained some 42 members of the fan groups as they confronted each other outside the stadium before the game, which eventually was won by the Liga Deportiva Alajuelense.
As police dispersed fans who were not allowed in the stadium due to prior behavior, the members of the barras ended up in small groups throughout the sprawling park. That is when police began to field complaints about drug use and unruly behavior. The remainder of the arrests were as a result of this problem, police said.
Those who create trouble at sports events can be barred under terms of the new law for as much as four years. The Fuerza Pública has set up a photo record of troublemakers.
The measure was approved in February after years of violent behavior inside stadiums and outside. Frequently rival fan groups would smash through barriers designed to keep them separate and engage in serious fighting. Outside, buses containing fans from one team sometimes were stoned by fans of the other team.