United are currently at the top of the table, three points ahead of Chelsea and having played one less game.
“A lot of teams are involved at the top of the table, maybe five teams,” said Ancelotti.
“For this reason, there are a lot of important games in the season and it’s too early now to say that it could be a decisive game.”
Chelsea won both meetings with Manchester United in the Premier League last season.
“It’s an important game also for your confidence,” said Ancelotti.
“We beat Man United last year. It was good for the mentality, for the character, for the personality of the team.”
