Arsenal hero Keown hails impact of Chelsea fullback Azpilicueta
He wrote in the Daily Mail: "In the first leg in Turkey Cesar Azpilicueta got forward a lot but it was business as usual on Tuesday evening.
"The Spaniard has replaced Ashley Cole because of his defensive qualities and that's partly because he is a right-footed player playing on the left.
"That makes him less inclined to push on as he ends up on his weaker foot, but it means he can deal more easily with wingers who cut inside.
"It makes him a very solid and effective option at full back, and that's exactly what Jose Mourinho wants."