Djokovic had already been successful with longtime coach Marian Vajda .
He had lost some of his edge in big matches and had perhaps grown too comfortable with his practice routines and in dealing with big - match preparation and pressure .
Djokovic had already been successful with longtime coach Marian Vajda , but he had lost some of his edge in big matches and had perhaps grown too comfortable with his practice routines and in dealing with big - match preparation and pressure .