The Rams were expected to win the Championship game at the City Ground, but they suffered a 1-0 defeat.
Nelson Oliveira’s goal in the fifth minute proved to be the difference between the two sides.
Clement believes that Derby’s failure to create chances was the main reason why they lost.
"We're to blame for not getting the right result tonight for the way we played,” the Englishman told BBC Radio Derby. “We lost a bit of identity.
"We were unable to create the chances we have in recent games, which was disappointing. It's a reality check for everybody. What we'll need to do now is reflect on it and get back to our way against Cardiff.”
Over the course of the 90 minutes at the City Ground, Derby had 66% of the possession, took 14 shots of which just two were on target, earned five corners and created 12 chances.
The Rams remain fifth in the Championship table with 30 points from 16 matches, a point behind leaders Hull City, who will face Middlesbrough at the KC Stadium on Saturday afternoon.
After the two-week international break, Derby will take on Cardiff City at the iPro Stadium in the league.