"Adel was outstanding," said Derry. "It was a last-year performance from him, when he was incredible, and his goal was from the top drawer.
"Hopefully that will give him the confidence to score more vital goals and produce those type of performances between now and the middle of May.
"He's got such raw ability that he absolutely took the league by storm last year. I don't know why it's taken so long to reproduce it."
QPR remain in the bottom three of the table on goal difference.