The Blues managed an impressive 2-0 home win in the Round of 16 first leg against the French champions.
He told BT Sport: "I was very pleased today, it took him a while.
"He struggled in the last matches with his belief and intensity and game in general.
"It was good he stepped up today and you can instantly see the impact he makes.
"He is our game changer.
"He had a huge impact on the team."