The playmaker feels his side have paid the price for two sloppy pieces of defending, as Pedro, Dani Alves and Victor Valdes all share their team-mate's sentiments
The Catalan giants had dominated first-half proceedings, with a 2-0 lead to show for their efforts, but two slack pieces of defending midway through the second 45 minutes cost them victory, as Sociedad pounced on both errors, and the 31-year-old highlighted their failings at the back as the reason for accumulating just a single point.
"We made two foolish mistakes in defence and they cost us dearly," Xavi told Barcelona's official website. "[They were] two isolated errors. From there on, their confidence grew and they showed more aggression than us.
"We weren’t expecting it," he continued. "We had the game under control until then and were looking to finish off the job."
Pedro agreed with his team-mate: "We had got the game on track in the first half but then we let in two goals and things became complicated. We should have scored more after making it 2-0, and we had chances to do it."
In addition, full-back Dani Alves echoed the sentiments of the aforementioned duo, but also was positive about rectifiying their problems in the near future, with a Champions League tie against AC Milan on Tuesday promising to be the vital tonic.
"It's hard to explain, but two mistakes cost us the match. It was a good wake up call. We have to be more careful," he said. "Football has been tough to us today, because they equalised with the only two chances they had.
"We're not panicking, but we know that to repeat our successes we have to repeat what we did before, and that’s not easy, and luckily, we have a very entertaining game on Tuesday."
Víctor Valdes also gave his two cents worth, where he was disappointed not to have capped Andoni Zubizarreta's appearance record with a victory in the Basque region.
"It has been a rather odd day," admitted Valdes. "I'm happy to have beaten Zubizarreta’s number of matches, but I’d prefer to have won."
"They got two goals to tie the game. Was it to our discredit or their credit? A bit of both, That's part of the game, and it shows nothing is easy. You have to concentrate for 90 minutes because it's no good to dominate the whole first half but not the second.
"We had it all under control in the first half, playing well from the back, and holding onto possession, but now we must think about the Champions League," he concluded.
Real Madrid's 4-2 win over Getafe means Real Madrid have overtaken Barcelona in the Primera Division standings.