Christensen has become Antonio Conte's first-choice defender at the heart of his three-man defence following on from the 21-year-old's assured and solid performances since David Luiz was dropped from the Chelsea squad in November.
"He's a really, really good player. He's comfortable on the ball, good defensively and you can see that week in and week out. He's playing and really enjoying it. It's really good to see that."
When then asked if he is surprised to see Christensen become a Chelsea first-team regular, Ake replied: "No.
"Everyone knew, also at the Academy, how good he was. And when he went on loan he done really well, and has been doing well in the national team so I wasn't surprised.
"He's a really good player."