Joe Dunne admitted he told his players a few "home truths" after seeing his Colchester United side thumped 5-1 at home by Tranmere Rovers.
Goals from Max Power, Jean-Louis Akpa Akpro, Ash Taylor, Cole Stockton and Michael O'Halloran gave Rovers an emphatic win at the Weston Homes Community Stadium.
Magnus Okuonghae scored what proved to be Colchester's consolation but the defeat leaves them three points adrift of safety in League One, with 13 games to go.
Dunne said: “It was a collapse in the second half and I’ve told my players what I think of it.
“We can’t make the mistakes we made defensively and not expect to get punished.
“We have a young changing room in there and there are a few of us who have lost 5-1 in there before.
“We have to respond and we can’t get downhearted – we have to keep going.
“I’ve told them what I thought and one or two got told a few home truths."
For more reaction to Colchester's defeat against Tranmere, along with a full match report and pictures from the game, see Monday's Gazette.