After suffering a last-gasp defeat to Real Madrid in last Saturday’s Clasico despite winning the game, Xavi Hernandez’s side inflicted the same suffering on Real Sociedad in San Sebastian.
Barcelona failed to create transparent chances until the round of 16, with goalkeeper Marc-Andre Ter Stegen holding the scoreline, before Araujo headed in Ilkay Gündogan’s cross with seconds remaining.
The win moves Barcelona into third place, two points ahead of Atletico Madrid, which lost to Las Palmas on Friday, and one point ahead of Real Madrid, which hosts Rayo Vallecano on Sunday.
Girona provisionally lead La Liga by three points over Los Blancos after beating Osasuna last Saturday.
“There are 3 very vital issues after the Clasico, which we lost playing well, it was vital to get the 3 songs,” Araujo told Movistar.
“We didn’t play well in the first half, we were a little bit better in the second. . . It was hard for us to come back, they pressed us well. “
Xavi has added Robert Lewandowski to Barca’s line-up after returning from injury as a substitute against Madrid.
However, the Polish striker remained as calm as he was last weekend, as he and Barcelona were close for long periods of the match.
Real Sociedad pushed the Catalans back in the first half, creating by far the most productive chances, but failed to place the first game.
In the first 30 seconds, Ander Barrenetxea beat Ter Stegen, and Barcelona’s German goalkeeper also denied Mikel Oyarzabal.
Ter Stegen was attentive to avoid with his foot a shot from Takefusa Kubo at the far post as Real Sociedad entered dangerous areas.
Barcelona presented very little at the other end of the pitch, prompting a capricious effort from Joao Cancelo in response.
Ter Stegen kept Martin Zubimendi on as the hosts continued to tighten the screws at the Reale Arena, playing with wonderful intensity.
Gundogan asked his teammates to show more after the Clasico capitulated, but he was as guilty as anyone, giving the ball away too much under Real pressure.
Fermin Lopez had Barcelona’s first shot on target in the first half, a weak and tame effort that he softly disguised through Alex Remiro.
Real Sociedad remained ahead after the break, but Barcelona found more stability, pressing back and completing some of the merits that Barrenetxea and Kubo had previously taken advantage of.
Pedri recovered from injury in the second half, replacing Lewandowski in his first appearance since August as Xavi sought more control.
Ter Stegen saved a Barrenetxea volley from the edge of the box, the 21-year-old’s latest contribution to a performance.
Substitute Ferran Torres fired in from the edge of the box, summing up Barcelona’s night up to that point, before the champions scored their first goal in stoppage time.
Pedri skilfully brought in Gavi, but Remiro denied the midfielder who found the net.
Their chance of winning was gone, but centre-back Araujo gave the impression of being in the right position at the right time to pull off the heist.
The defeat leaves Real Sociedad sixth, after Real Betis beat Mallorca to overtake them.
“In general we were bigger than them, we didn’t let our chances pass us by and they scored the one they had,” Oyarzabal told Movistar.
“I think it’s worse to lose without showing up, to lose without betting well. . . We were all looking to win and we had a chance to do so, but if I have to lose, I would lose like this. “