See, I didn't think it was "great" at all.
He played well going by what you'd expect of a defender playing in midfield. Pretty much as well as you could reasonably expect someone to play in that situation. If he was an actual midfielder I would have considered it a limited performance and expected a lot more. We effectively surrendered the middle third of the pitch, in a home game.
I still don't know what these "great" midfield performances from Phil Jones that people refer to are. The only game in which he's bossed the midfield was at home to Wolves, during the season they were pathetic and relegated, and even in that game Carrick was the best player on the pitch.
If the idea is for him to fill in some kind of occasional specific role there then last night was a promising sign that he can, but he's got far too much potential to be wasted as some utility alternative to having an actual midfield option in order to paper over cracks. He has the ability to push for a place as one of our first choice centrebacks, if he ever actually gets to play at centreback for more than one game out of every three he's picked for.