Chelsea risk enduring another "bad season" if they do not improve defensively, head coach Antonio Conte has warned.
Conte was not particularly happy after watching Chelsea lose 3-2 to European champions Real Madrid in Saturday's International Champions Cup match in Michigan.
Chelsea struggled early against Madrid, trailing 3-0 at half-time before Eden Hazard's late brace reduced the deficit in front of 105,000 supporters.
While acknowledging the tiresome travel across the United States, Conte called on his players to improve their work without the ball as a unit if Chelsea want to return to the Premier League summit, having finished 10th last season.
"After this game, it's clear we have to always work together, without the ball and with the ball," Conte told reporters as he reinforced his message.
"If we think we don't have to work without the ball, it is not possible for us. We risk repeating a bad season.
"Today I think we weren't a team in defensive situations. We were better with the ball but bad without it."
Conte added: "My aim now is to become a team. Inside and outside of the pitch
"It is important to reach our target at the end of the season.
"I know with my experience as a player and a manger, that if you want to reach the target and fight for the title, you must be a team, on and off the pitch.
"We must become a family. This is the key to switch from last season. If we don't understand this, it is not good."