first goal for Universidad de Chile. During the year he played 36 games between the Apertura and Clausura tournaments. After of the departure of Arturo Salah and the arrival of the Uruguayan coach Sergio Markarián, Díaz was used as a left back, unlike Salah that used him as an attacking midfielder. On 28 January 2009, he scored his first international goal in a 1–0 home victory to Pachuca. In the first semester of the season he won his first professional title, the Apertura Tournament, that his club won after beating 1–0 Unión Española in the playoffs final. The next season, now with the arrival of Gerardo Pelusso as the coach, Díaz was being used as right back and only played five league games. On 13 August 2010, the player confirmed his incorporation to Deportes La Serena. There, he returned to the midfield, being deployed as an attacking midfielder. On 22 August, Díaz debuted in a 4–0 home win over Santiago Wanderers at La Portada Stadium. In his third match for the club against Audax Italiano, he scored his side's goal in a 2–1 defeat in the 86th minute. On 3 October, Díaz scored a brace in a 3–3 draw with Everton, being red carded in the 91st minute. After a one match absence, and his return in the game against Unión Española, he again scored his side's goal in a 2–1 away defeat with Universidad Católica. On 28 November, Díaz had a successful performance against Cobresal, being named the man-of-the-match and scoring a goal in a 2–0 win. Having finished the 2010 season, Díaz had a deal with Huachipato for a loan, but Universidad de Chile's new coach Jorge Sampaoli wanted him to play for his team in 2011 and the player remained in the club. Breakthrough seasons Díaz began the season as a substitute player replacing to Guillermo Marino in all second halves of a game, but due to his good performances, he ended up replacing Marino on the starting lineup. On 4 June 2011, he scored a wonderful 26-yard free-kick versus O'Higgins, in Universidad de Chile's amazing 7–1 rout for the playoff's semi-final. Following the title obtained in the Apertura Tournament and the departure of Felipe Seymour to Italian Serie A side Genoa, Díaz started to play in Seymour's former position in the starting lineup as a central midfielder, with a more defensive role. When the Clausura Tournament