The Royals led the Championship opener through Jon Dadi Bodvarsson, but the Rams recovered and netted a last-gasp winner to begin the campaign with a win.
Clement has said that the result at the Madejski Stadium was 'harsh' on his side, but acknowledged that more could have been done to earn a share of the spoils.
The 46-year-old is quoted by the Reading Chronicle as saying: "Clearly if you lose the game with the last kick it is tough. Particularly the first game of the season.
"We have just got to make sure we don't lose it. It was a fantastic cross and header. We did well in the first half. Our shape was fantastic. Derby changed their style in the second half and spaces opened up as players tired.
"It is a harsh result and a big lesson for us so early in the season. Our goal was a great goal."
Reading are next in action when they face Nottingham Forest at the City Ground on August 11.