Carrick faces his old club today at White Hart Lane.
"You would have to say it is the best Spurs team we've seen for a while. They have certainly improved on years gone by and become a big threat this season," he said.
"Tottenham have some major threats, particularly in wide areas with Gareth Bale and Aaron Lennon. Luka Modric has been in good form, as has Rafael van der Vaart, who has weighed in with a good few goals as well so I expect them to pose us a few problems.
"I am not exactly sure what Harry has done to turn things around.
"Just knowing how to get the best out of his players is a major factor.
"When you are a manager, you need a feeling for what is required at each different stage and how to treat certain players.
"You can see they're playing with confidence and they'll be looking forward to this as much as us."