The Cats surprised the Kangaroos with an eight-point win in round three, a loss Pagan rated as a missed opportunity.
``Maybe we thought we were a little bit better than the Cats and they proved they're equal to anyone in the competition and you certainly can't not respect your opponents,'' he said.
``I don't know if that was the case, it was certainly sloppy in a lot of areas but perhaps with a real good wind-up and a real stiff concentration it could have been done a lot better, that game.''
Speaking ahead of Saturday's return clash at Skilled Stadium, Pagan said Geelong was a genuine premiership contender.
``Everyone makes a contribution, they don't rely on one person,'' he said.
``It starts off at the centre bounce through (ruck) Steven King and guys who are not actually household names have really been performing and getting telling possessions and winning the contests that matter.
``They're certainly taking everything in front of them and they've really had a good season.''
The Kangaroos are ninth on the ladder after being blown away in an eight-goal first quarter by the Western Bulldogs last weekend.
Pagan said it was imperative the Roos' found the form of the previous week, when they beat premiership fancy Port Adelaide.
``We started terribly,'' Pagan said of the loss to the Bulldogs.
``Our approach and attitude wasn't anywhere near what it was the week before. Whether you can get to that fever pitch every week I don't really know, but I know they were sharper and when you look back at the game it was all over 10 minutes into the first quarter.''
Kangaroo midfielder David King missed training yesterday after receiving a kick to the shin against the Bulldogs, while rover Brent Harvey (shoulder) ran laps and will miss at least one game.