Michael Chopra put the Bluebirds in front with his 10th goal of the season before Arsenal loanee Jay Emmanuel-Thomas wrapped up the points in the 90th minute.
Pearson said: "We came up against a good side and when we had chances we were unable to take them.
"I was disappointed with how the first goal came about. It was a nothing goal and it wasn't like us. The second goal put a slightly different slant on the result.
"In the last couple of months we've done to sides what Cardiff have done to us, and you have to recognise we came up against a good side and they were better than us.
"The players are very disappointed because we know it's a game we could have got something out of, and that shows how far we've come. But we need to bounce back. The bigger picture is that we could say it's a missed opportunity, but another way of looking at it is that we haven't lost ground either."