The 27-year-old revealed last week that he had struggled to cope after heading straight from his first campaign in British football to the Euro 2012 finals and then back into Premier League battle.
Pardew said: "Obviously we, and particularly myself, had to help him through that stage. It was difficult for him.
"Physically and mentally, he hadn't coped with anything as strenuous as last year. To fight for the Champions League and become a regular in the French side and the championships took it's toll on him.
"But he has certainly come out of the other side a stronger person. He is a fantastic character.
"He is one of our best players, if not our best player, and he is back to his very, very best and we are very, very lucky to have him."