Career
A player of good dribbling skills, he is also a penalty kick specialist. However, on 23 May of the following year, as the league"s outcome was already decided, he profitted from his second start to score twice against Real Madrid in a 4–1 away success, one of the goals coming from the penalty spot. Subsequently Prieto was definitely promoted to the first squad and, in 2005-2006, participated in all 38 games and netted nine times, six of them being penalties.
In the following season he was also everpresent, but the Basque dropped down to the second division.
Prieto played in 35 matches in the 2009-2010 campaign, totalling exactly 3,000 minutes and contributing with seven goals as Real Sociedad returned to the top level after three years. In the first game of the following season, at home against Villarreal CF, he scored the game"s only goal, after a backheel pass from newly signed Joseba Llorente.
On 6 January 2013 Prieto netted the first hat-trick of his professional career, but in a 3–4 loss at Real Madrid: he scored once through a penalty and twice after one-on-one situations against Iker Casillas.