The Belgium international was wanted by Zidane to sign for Real Madrid.
"He has immediately adapted to the Premier League. Hazard, a player with the most assists to his name, is already one of the most important pawns on the chessboard of (Roberto) Di Matteo," said Zizou.
"He is a player with a personality on the field. He gives fans pleasure. Whatever his age, he makes a deep impression on me. He lets the others play better, that's his strength."