Shaun Maloney savaged his Hibs side after surrendering a lead to Hearts and dropping into the bottom six.
The Easter Road boss insists he won't accept the manner of the collapse from his players who went down 3-1 with a whimper in the Edinburgh derby at Tynecastle.
As a post mortem began on the Leith side being consigned to seventh spot at the Premiership split, Maloney admitted his disappointment at the failure of his side to react to the game's decisive moments.
He said: "What was most disappointing was that the two big moments in the game, just before half-time and straight after, had too big an impact on how we played.
"We were very good in parts of the first half, but we can't allow a set-play goal in the second half, after a couple of minutes, to then completely alter how we played and the mentality of the team.
"That's the biggest disappointment. The performance in the second half, I can't accept, and I won't.
"I understand at this time of the season, the results are even more magnified but I think, when I came in and we were seventh, I saw traits that at times we've eradicated but what you saw today in big, big moments under the biggest pressure, these traits come out. "And that's why we find ourselves in seventh again.
"We've really struggled in that final area, and I know we have some young players who have to learn, but they have to learn very quickly. We've got an opportunity next week to put things right so we have to learn very, very quickly.
"We conceded a set-play, that can always happen. At times in the first half we were very good but we can't then allow a set-play goal to completely change that. It completely changed our performance in terms of how we competed and that can't happen."
Maloney will now attempt to lift his side for Saturday's Scottish Cup semi-final against the Jambos and he's adamant Hibs need to get their act together quickly with this result meaning he could wield the axe.
He said: "It will definitely have an impact. Performances should always have an impact. I'm very aware of what people do in training each day and their behaviours, but the biggest one is the games and how people perform in games will generally dictate who plays and that should always be the case, but we'll look at that next week.
"The players have an opportunity next week to put it right. We can't accept that, we can't think that that's going to be good enough for top six, top four, or challenging for Europe.
"I understand we have some young players but they have to learn very quickly that it matters, and it matters a lot - to them, to the club, and to their careers.
"That's the biggest disappointment, when we come here and play as well as we can for the first 30 minutes. It's not good enough.
"We could talk about everything, how we play, the style of play, but the bottom line in every team is that you have to compete.
"It's in those biggest moments, when you go 2-1 down at your biggest rivals, can we still go and compete? Today we showed that we didn't.
"We have to change that very quickly, we have an opportunity next week but what I saw today tells me - although I already knew - the reasons why we were seventh then, and why we've now dropped to seventh.
"We've got a lot of work to do between now and next week, and even more work for next season to make sure we don't perform like we did in the second half."
