Aimar scored the last goal of the 2005 FIFA Confederations Cup during Argentina's 4–1 loss in the final to champions Brazil. He also appeared with the national side in the 2007 Copa América, scoring a goal in a 4–1 win against the United States in his team's opening group match of the competition; Argentina went on to reach the final of the tournament, losing out to Brazil once again, this time 0–3, with Aimar coming on as a second-half substitute for Cambiasso.