 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.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.