On 11 June 2015, Vargas scored for Chile in the opening match of the 2015 Copa América, a 2–0 win over Ecuador at the Estadio Nacional in Santiago. In the team's next fixture, Vargas scored his second goal of the tournament, heading an equalizer as the hosts drew 3–3 with Mexico on 15 June. In the semi-final against Peru, Vargas scored both goals in a 2–1 victory for Chile, the second of which was a long-distance effort, to send "La Roja" to the final. Although Vargas was substituted out in extra time, Chile won in a penalty shootout against Argentina to win their first major international honour. Vargas' four goals made him the competition's joint top scorer alongside Peruvian Paolo Guerrero, and he was named in the Team of the Tournament.