On 31 October 2015, Medel scored his first goal for Inter to give the Nerazzurri a 1–0 victory over Scudetto rivals Roma at the Stadio Giuseppe Meazza.
At the 2015 Copa América, held in Chile, Medel scored during a 5–0 win against Bolivia which ensured that La Roja would progress to the knockout stage as Group A winners. In the semi-final against Peru, he scored an own goal from Luis Advíncula's cross to equalise, but Chile advanced to the final winning 2–1. In the final against Argentina, Medel played as a starter and helped the team to win the trophy on penalty kicks, after the regular time ended in a goalless draw. Medel became the fourth most capped player with 80 matches, equaling his defence partner Gonzalo Jara. That was Medel's first major trophy with Chile. For his performances he was named in the Team of the tournament.
Medel usually plays as a defensive midfielder; however, he is also capable of playing as a defender, and has even been deployed as a centre-back throughout his career, as well as in other midfield roles. Due to his work-rate, physicality, tenacity, tactical intelligence, and his aggressive, hard-tackling style of play, as well as his leadership on the pitch, he is nicknamed Pitbull. In 2015, manager Roberto Mancini described Medel as a warrior.