Clearly determined to make no further additions to a terrible record that had seen them lose 19 of their previous 22 clashes against Barcelona, Sociedad had the ball in the net after just 28 seconds, and Barcelona were clearly relieved to see the offside flag, before Pedri then extended Alex Remiro at the other end with not even two minutes on the clock.
Within seven minutes of the kick-off, Fermin Lopez looked to have hammered home the opener, but after a VAR review, the official decided there was a foul in the build-up.
Frenkie de Jong then had an effort ruled out for offside, before Dani Olmo missed a sitter from 10 yards out.
Incredibly, Lamine Yamal had the fourth ‘goal’ of the half also chalked off, and Sociedad capitalised just after the half-hour mark out of virtually nothing.
Mikel Oyarzabal volleyed home at the far post to give the hosts the lead, and a penalty awarded to Barça in stoppage time got overturned by VAR, ending the half as it had begun.
Olmo hit the post two minutes after half-time, and Remiro had to be alert to Ferran Torres’ snapshot as Barça pressed again.
Still, the hosts held firm, forcing the visitors into a triple substitution just after the hour mark.
One of those who came on, Robert Lewandowski, soon saw a trademark header pushed onto the bar by Remiro, before another sub, Marcus Rashford, finally headed home an equaliser with 20 minutes to play.
But within a minute, Goncalo Guedes restored Sociedad’s lead after some lax play at the back from Barça’s back line.
Barcelona were suitably rocked, and Pau Cubarsí’s goalline clearance - after Joan Garcia had gone walkabout - kept the game alive for the Blaugranes.
Jules Kounde’s bullet header then bounced back off the crossbar, before Barça were handed a late advantage after Carlos Soler’s yellow card for a challenge on Pedri was upgraded to a red.
Naturally, it wouldn’t be an endgame without at least one Barcelona chance - especially with nine minutes being added on - and Rashford hit the post directly from a corner in stoppage time, but it just wasn’t Barça's night.
The result means that Barça couldn’t equal the feat of 10 successive wins they last posted in March 2016, with Sociedad now unbeaten at home against the Catalan giants in the last two fixtures.
Flashscore Man of the Match: Frenkie de Jong (Barcelona)
