The legendary Frenchman has claimed that being played on the wing during his time with The Reds hampered Cisse's progress.
"Benitez slowed down his career by playing him as a right winger," blasted Roux in L'Equipe.
"He preferred to play the players he has signed in the centre.
"I watched Cisse last Wednesday for Marseille against Auxerre. He didn't miss a single pass. It is untrue to say he has technical weaknesses. He has made huge improvement on that level."
Roux has also heaped praise on Cisse's attitude and the way he has come back from two broken legs.
"His character? He has great reactions and an excellent state of mind.
"Cisse has been outstanding with his team-mates. How many players would have sulked? Moreover, do you know any boy who has two broken legs and plays football like him?"