Barcelona beat Chelsea at the Camp Nou to book a place in the draw for the Champions League quarter-finals due to take place on Friday.
Dembele scored his first goal for the Catalan club and the 20-year-old is now fully fit following a period on the sidelines due to a ruptured thigh tendon and a hamstring injury missing 27 games in total for Barcelona.
"He worked a lot in attack and made a crucial defensive display. He took a step forward," said Barcelona manager Ernesto Valverde. "We hope he keeps taking advantage of the opportunities he gets. He had the injuries, and was coming from a different team and a different type of football.
"He has to adapt to how we play in attack and defence."