Vassell is confident Mahrez will make a big impact for the Foxes.
He said, “I think he will rise to the occasion, that's what great players do.
“Pep Guardiola will look at him as a player and will want to improve him and probably make him the world star he deserves to be.
“It might take time for him to bed in and he might not get as much match play as he would want given the talent that Manchester City have in their squad.
“But when he does get his foot on the ground and running, we are going to get beautiful football once again from Manchester City.
“I think his preferred position is coming off the right onto his left foot. It just gives City an extra dimension and is a great signing.
“He did his best at Leicester but it is about time we saw him at a top team."