On September 10, 2006, during the halftime of a match against Boca Juniors, club president Juan José Muñoz confronted (and allegedly threatened) referee Daniel Giménez, who called off the match immediately, with Gimnasia leading 1–0. Muñoz was reprimanded by the football association and temporarily removed from its executive committee, although he was confirmed as Gimnasia's President by the club's board. A few days later, Gimnasia was eliminated from the Copa Sudamericana by the Chilean champions Colo Colo, following a quarter final match where a player of Gimnasia was injured by a cement piece thrown by Chilean supporters. Due to Gimnasia's physical play in the second leg of the quarter finals in Argentina, Argentine Football Association's president Julio Grondona wrote a personal letter to the president of the ANFP (the Chilean football federation) apologizing for the "roughness" of the Gimnasia players.