Argentina star, Lionel Messi scored his 19th goal of the season just before the hour mark to cancel out Willian Jose’s header, but a largely poor performance from the champions meant their nine-year wait for a win at Anoeta goes on.
Barca had lost on their last four league visits to San Sebastian and that record looked to be playing on their minds in a nervous and deeply disjointed first-half display in which they failed to register a shot until the 41st minute.
Sociedad had been by far the better side and were good value for the lead when the breakthrough came shortly after half-time, with Willian Jose’s effort being sliced into his own goal by Gerard Pique as he covered the goal line.
Messi responded soon afterwards following good work from Neymar, but a winner for the visitors never looked likely and Carlos Vela crashed an effort off the underside of the crossbar from 20 yards before Juanmi’s rebound was unjustly ruled out for the hosts.
Denis Suarez had a shot blocked and Javier Mascherano steered a header narrowly wide, before Vela clipped the base of the post with another effort that had Marc-Andre ter Stegen beaten.
Ultimately there was to be no winner, however, meaning Sociedad miss out on the chance to move above Atletico Madrid into fourth, while Barca could only close to within six points of league leaders Real Madrid.