Millwall boss Neil Harris bemoaned a "criminal" period of five minutes as The Lions lost 3-0 to Derby County at Pride Park in the Sky Bet Championship on Saturday afternoon.
The visitors more than competed during the afternoon and fashioned countless chances, but were unable to score the goal - or more - that their play thoroughly deserved.
Three goals in five first-half minutes, however, ultimately ended the game as a contest.
"We've had a lot of big moments like that on the road this year, where we've not taken our opportunities at key moments and been punished," said Harris. "That's the difference between Derby - in the top six - and us - not in the top six.
"When chances come along, Derby take them. We've been punished for three or four errors today by conceding three goals. We've had numerous chances, clear-cut chances, and not taken them. That's the frustration for me, but also the realism of where we are.
"I'd have rathered the response came after the first goal! We needed to be more professional and disciplined. Our game management should have been better at 1-0. We give away a poor goal and then we don't focus. They're too occupied with watching the goal back on the big screen and not getting back into shape for a big five minutes.
"As a club like us, we can't afford to have five-to-ten minute spells like that. We gifted Derby the goals - the goals were good, but we have to make sure when we concede, it's about how we react. To concede two more goals in the space of five minutes is criminal. I'm disappointed in my group for that."
Harris explained how eyes would quickly turn to Boxing Day's visit of Wolves to The Den, but also issued a reminder to his players after the first-half capitulation.
"I've reminded the players that if anyone was getting a little ahead of themselves after seven points from the last three games, that's a reality check.
"We'll take that on the chin, re-build and move on to Wolves on Boxing Day."