Andy Peaks pulled no punches after AFC Rushden & Diamonds slumped to a second defeat in a row in the Evo-Stik Northern Premier League Division One South.
Diamonds went down 3-0 at Basford United, who moved level points with them as a result.
Peaks’ team conceded three headed goals and were 3-0 down inside 49 minutes and it left the manager fuming.
He accused his players of “letting the club down” after they were unable to bounce back from the midweek home defeat to Spalding United.
Diamonds remain in the final play-off position but now have Basford and Leek Town breathing down their necks.
And Peaks said: “The defending for the first two goals was poor and then we have given them another one early in the second half.
“We have lost to three headed goals, they were unchallenged and pretty much free headers.
“I am really disappointed because I think the players have let me and the club down and I told them afterwards that it wasn’t good enough.
“It’s important we turn this form on its head by this time next week.
“The performance levels have got to be a lot better because we slipped well below the standards we have set.”
Diamonds are back in action on Tuesday night when they make the trip to mid-table Chasetown.