Last Blaugrana win in Donostia dates back to the 5th of May 2007
On Saturday Barça play in Donostia one of the key games to the title. After the setback against Real Madrid in Camp Nou, to get the 3 points in Basque territory would help tremendously to consolidate the lead in La Liga (especially if Atlético Madrid doesn't win in Espanyol's stadium or if Madrid doens't beat Eibar in El Bernabéu.
However, the Blaugrana's last results show that Anoeta not is an easy place for the team. The last Barça win on Real Sociedad's ground was in the 2006/07 season (already 9 years ago), when Frank Rijkaard was the coach. On that 5th of May 2007, Iniesta and Eto'o had scored the 2 only goals of the game.
From that day on, (and taking into acount the fact Real Sociedad went to second division), Barça have been 5 times to Donostia to play La Liga games (in February of 2014 they played there a Copa del Rey semi-final that they drew 1-1). The balance is poor: 1 point (draw in the 2011-12 season) out of 15, since the other 4 games were losses.
Going even further back, Laia Tudel explained in the Club de la Mitjanit on Catalunya Radio that, since the first season of Joan Laporta as Barça president (2003/04), the Blaugranas have lost 66% of the points that were in play in Anoeta. This percentage is way worse than the one they have got in Santiago Bernabéu (43% of loss points) or in other stadiums difficult as well as Vicente Calderón or San Mamés (45%).
This lack of efficiency is a surprise in a stadium that, a priori, isn't especially dangerous for Barça: it isn't a hostil stadium towards the team, and Real Sociedad have had different teams coached by different managers. On Saturday, however, we'll see if the bad streak continues.