The Belgian ace, who struggled with his form last season, is already showing signs of improvement under Antonio Conte and has scored two league goals in the opening three games, which has Ivanovic excited.
"We are playing like a team, but you also look at the players and their potential. Eden is one of the best players in the world," said Ivanovic.
"He is the player that can decide the league, everything, and every game we play.
"Everyone hopes we continue get his performances from two years ago. With that we can do incredible things."