Andrew Robertson admits Napoli made Liverpool look like fools on Sunday.
The Reds were seen off 3-0 by Carlo Ancelotti's Italian side with Lorenzo Insigne, Arkadiusz Milik and Amin Younes all scoring at Murrayfield.
Robertson has warned his team-mates to improve or risk further damage in their Community Shield clash with rivals and Premier League champions Manchester City on Sunday.
He said: It wasn't good enough. We were miles off it. We were outplayed. At times we looked foolish by not pressing as a team.
And we need to look at it and improve as our season starts in a week and it doesn't get any harder than Man City.
We need to be a hell of a lot better than this.
Jordan Henderson and James Milner pulled us in for a huddle on the pitch and what was said cannot be repeated until after 9pm. It's not crisis meetings, it's pre-season.
But we can't get into a habit of losing or drawing. We need to step it up massively."
