Stephan El Shaarawy scored twice as Roma moved above the Blues, who could have progressed to the knockout stage with a win, to the top of Group C. Chelsea will go through if they beat Qarabag in their next group game.

"If you are a great team, you must have stability and consistency," said Conte. "In this moment we are struggling to have this balance."

The Italian guided the Blues to the Premier League title in his first season - with just five defeats in 38 games. They go into Manchester United's visit on Sunday fourth in the table, having lost three of their opening 10 games.

"I don't know what will happen against Manchester United," said Conte. "They are a really good team. We must find the hunger that we showed last season and in this season sometimes. This season is up and down."