 He made his debut on 17 July, on a UEFA Champions League second qualifying round first leg fixture, a 2–0 away victory against Flora Tallinn.Díaz scored his first goal for Basel during the return leg against Flora Tallinn, from a free kick, on 24 July.He made his Swiss Super League debut for Basel in St. Jakob-Park during the 2–2 home draw against Luzern on 21 July 2012.