The incident overshadowed a forgettable match in which Alejandro gave Uruguay a first-half lead before Ivan Zamorano equalised for Chile with his third goal of the tournament. His striking partner, Marcelo Salas, was less proficient, missing a penalty which could have earned his side victory.
Uruguay will play either Brazil or Mexico, who were due to stage the second semi-final, at Ciudad del Este, early this morning.
Acosta was sent off shortly after Chile's equaliser but, instead of being allowed to go quietly to the stands, he was surrounded by five armed officers who led him away. "It was abhorrent, humiliating and disrespectful of the police to take me from the field in the way they did," Acosta said. "Instead of protecting you, they try to remove you from the field of play. They were trying to attract attention by doing something which is not part of their job."
Uruguay reached the final despite resting their European-based players after a long season with their clubs. The game, played in a near-deserted stadium, was possibly the worst of the tournament.
The result means Uruguay have managed to win only once in normal time on their way to the final, having needed penalties to get through both their quarter-final and semi-final matches.
Extra time is not played in the Copa America and in the penalty shoot- out, Chile's Mauricio Aros was the only player to miss when his effort was saved by Fabian Carini.