The Gorgie outfit prevailed 3-1 at Tynecastle, with other results condemning Hibs to the bottom half of the cinch Premiership after the split.
“The performance in the second half I can’t accept and I won’t,” said Maloney.
“We can’t accept that, we can’t think that is going to be good enough to make the top four, to challenge for Europe.
“I understand we have some young players but they have to learn very quickly that it matters – to them, to the club and to their careers.”
Seventh when Maloney took over from Jack Ross in December, the Leith club will be unable to improve on that now, losing goals either side of half-time and then a third in the 58th minute to lose the first in a derby double-header 3-1.
“I can understand at this time of the season results are magnified and when I came in and we were seventh, the traits that I saw we have at times eradicated, but in the big moments, under the biggest pressure those traits come out. That is why we are seventh again,” Maloney said, blaming the players’ ability and mentality.
“In the second half we were below the level required for both.
“I know we have some young players who have to learn but they have to learn very quickly.
“What was most disappointing was there were two big moments just before half time and straight after which had too big an impact on how we played.
“Hearts were very good but we can’t allow a set play goal in the second half after a couple of minutes to completely alter how we play and the momentum of the team.
“We concede a set play, that can always happen, but we can’t allow that. At times in the first half we were very good and it completely changed our performance in terms of how we competed. That can’t happen.”
There is an opportunity to make some amends at Hampden next weekend, when they face Hearts again, this time in the Scottish Cup semi-final and he admitted he will have some decisions to make ahead of naming a team.
“It will definitely have an impact. I think training is a big thing but the biggest one is games. How people play in games will generally dictate selection and that should always be the case but we will look at that next week.
“Some people had a difficult day but we’ll need a full squad next week. But, generally, performances will dictate if players stay in the team or not.
“In every team you have to compete and it’s in those biggest moments when you go 2-1 down at your rivals that you have to still compete. Today we showed we didn’t. We have to change that very quickly and we have an opportunity next week. We’ve got a lot of work to do between now and next week and then more next season to make sure we don’t perform like we did in the second half.”