Mike Phelan launched a stinging attack on his Hull City side after their 6-1 defeat to Bournemouth, insisting they must "grow up" if they are to fulfil their potential.
A Junior Stanislas brace and further goals from Charlie Daniels, Steve Cook, Callum Wilson and Dan Gosling ensured the Tigers endured an afternoon to forget at the Vitality Stadium.
Hull sit 16th in the table with the worst goal difference in the Premier League after conceding 17 goals in their last four league games.
And Phelan, who was named on Friday as the Hull head coach until the end of the season, did not hold back in his assessment of his side's display afterwards.
"I feel very embarrassed. I've got a team here who show what they can do when they want to," he told BBC Sport.
"We've got to grow up. Unless we concentrate and be disciplined, we won't get to where we want.
"What we've done is not good enough.
"I thought we were victims of our own downfall in some respects. We're conceding far too many and I'll take responsibility for that.
"We tried to be proactive, we tried to be on the front foot, we probably overexposed ourselves a little bit, and that's down to the planning issue.
"I will look at myself, players will look at themselves and we start again. We'll learn, but we have to learn quickly."