It's fair to say the main talking point from Barcelona's defeat to Real Sociedad was the controversial decision to rule out Robert Lewandowski's goal for offside.
Lewandowski thought he had made it 1-0 in the 13th minute but VAR decided otherwise. It was a baffling decision at the time and became even more baffling as images were released and went viral on social media.
After studying the footage, VAR decided that Lewandowski was offside by a toenail. However, Barca feel that there's been an error and VAR have used Nayef Aguerd's boot and not Lewandowski's.
Hansi Flick knew it was a goal and said as much after seeing his team slip to their second La Liga defeat of the season. We'll never know if the result would have been different if Barca had gone ahead but Flick will know this was not a good performance from his team.
The Catalan giants stay top of the table over the international break and will now have time to reflect on what went wrong and how to put it right. However, expect the controversy caused by VAR's decision to rumble on for a little while.
Barcelona were without Lamine Yamal against Real Sociedad due to injury and the 17-year-old was badly missed. The visitors didn't manage a single shot on target all night long, while Jules Kounde looked a shadow of himself without the teenager in front of him.
It won't have slipped Flick's attention either that Barcelona's two defeats of the season in La Liga have both come when Yamal was absent (against Osasuna and now against Real Sociedad).
Of course the absence of Yamal is not the only recurring theme from the two defeats. Both games were fairly chaotic, with Barca struggling against a smothering press and seeing their opponents able to beat the famous offside trap.
Barca's attack looked unbalanced without Yamal. Raphinha was shifted wide and couldn't continue his stellar form, while Dani Olmo improved things after coming on at half-time but faded as the game wore on.
Flick admitted his side made "bad decisions" in the final third but will also know Yamal cannot play every game and that he must find a way to cope without the 17-year-old in the team.
Sunday's result will bring Barcelona crashing back down to earth after a superb couple of weeks that have brought impressive wins over Bayern Munich and Real Madrid and had left the Catalans feeling almost invincible.
Yet Real Sociedad showed that is very much not the case and Barca can be beaten. La Real came into the match with a horrible home record but played with an incredible intensity to take the three points that will have left Hansi Flick with plenty to think about.
The German had declared Frenkie de Jong able to play 90 minutes ahead of the match but saw the Dutchman come off at half-time. De Jong has been out for a long time with an ankle injury and still seems reluctant to go all out just yet.
Flick also looks short on back-ups for players such as Yamal, Robert Lewandowski and Alejandro Balde which will become more of an issue as the season progresses and more rotation is required.