Rooney became only the fourth player in United history to reach 200 goals for the club when he scored twice in Tuesday night's 4-2 Champions League win over Bayer Leverkusen.
Manager David Moyes has already set Rooney the target of netting the additional 49 goals needed to join Sir Bobby Charlton at the top of the club's scoring charts.
It is not a milestone the 27-year-old can achieve this season.
However, in his present form, Carrick knows Rooney can cause some serious damage.
"It was as good as I've seen him for a while," said the England midfielder.
"He looked sharp and he looked hungry.
"His movement and touch was all there and he showed exactly what a player he is.
"It's great to have him in that kind of form."
There was never any real doubt once United dug their heels in over the prospect of Rooney joining Chelsea this summer that he would still try to perform at his best for his current employers.