Still yet to see a CB pairing with Koundé be as solid as the Araujo - Christensen partnership was last season in majority of games. As others pointed out, better teams than Sociedad are bound to capitalize on one of his mistakes in the CL knockouts.
Feels a bit as if Xavi might be playing favourites with him or is insisting on him due to his price tag. Christensen hasn't been as good as last season, but would still feel calmer with him and Araujo at the CB pairing for big games, definitely seems as the pairing the compliments each other the best IMO.
It's not that Koundé has been bad, but think that some of his performances get overrated due to his last minute tackles and such. Christensen in comparison is much more passive, positionally better and more anticipating, leading to him standing less out.
Inigo also seems quality, and can offer something different being left footed.
Overall really good depth at CB, but have yet to see a better pairing than Araujo - Christensen for big games, and think it's a bit odd that Christensen suddenly seems to behind Koundé and maybe even Inigo in the pecking order?
Maybe I'm a bit biased being Danish and seeing Christensen perform so well for the national team, essentially leading our defense.