Don't get me wrong. Never wanted him when we were linked in his younger days (circa 5-6 years ago) because of his injuries and a plus 20m price which sounded like more back then.
But on a free, he was always a better stylistic match than Rudiger (I think I did recommend Rudiger as few years back when he was out of favour mind you).
Solid defender with good discipline, no bullshit in his game. One moment in the game I remember well - Christensen won the ball in the middle and noticed Balde making a run behind Real's defensive line, but instead passed the ball to nearby Busquets. Whether he's not confident in his long passing or just assumed it's too risky position which could lead to counter attack, I don't know.