 In the match against San Lorenzo in November, Falcao injured the ligaments of his right knee and missed the remainder of the Apertura; then, during pre-season training in January 2006, he sustained more serious damage to the same knee, which required surgery and was expected to keep him out for at least six months.He returned to the field in September, soon after the start of the 2006 Torneo Apertura, in which he made 12 appearances, mainly as a substitute; he scored just once, to seal a 2–0 win against Rosario Central that took River clear at the top of the table.A few days earlier, he made his debut in CONMEBOL competition, in the last eight of the 2006 Copa Sudamericana against Atlético Paranaense of Brazil.