The Rams lost 3-0 at home to the Reds in the third round of the league cup and despite it being a disappointing night at the iPro Stadium, Pearson suggests it was a first-hand lesson from a quality top flight outfit.
"Something that people forget about the Premier League is that it is not just about technicality," he told Rams Player HD.
"That is a factor, of course, but they're all athletes and to be effective in the Premier League your players have got to be as good as they can be.
"It is always a distinct illustration, when you play against a Premier League side, to see how athletic they are and their ability to deal with the physicality of games."
Ragnar Klavan, Philippe Coutinho and Divock Origi were all on target for the Reds as they dumped Pearson's Derby from the league cup.