Denmark boss Morten Olsen criticised his side's performance despite their comeback to earn a 2-1 win over Cameroon on Saturday.
Despite the spirited fightback, Denmark's performance was riddled with individual errors, the first of which from Christian Poulsen gifted Samuel Eto'o the opening goal.
Olsen's side steadied the ship and began to play some attractive football, levelling before the break through Nicklas Bendtner with Dennis Rommedahl completing the turnaround after the hour mark.
Simple errors continued from both sides but Cameroon were unable to punish the Danes and as a result become the first nation to be officially knocked out of the tournament.
Whilst being happy with his side's fight, Olsen admits he has some coaching to do before his side take on Japan on Thursday in a winner takes all Group E showdown, with Holland having already qualified.
"We made far too many elementary mistakes and I can't allow that from my players," Olsen said.
"So I wasn't happy actually. Of course the players fought heroically, some of them didn't play well today I have to say, but they fought.
"We must correct that if we are to progress in this tournament. Some didn't play well but they fought.
"We had Nicklas Bendtner, Jon Dahl Tomasson and Daniel Jensen on the pitch, and those players haven't played much.
"But that's the way it is, that's why we had to fight so much. We had nothing more to offer, we have too many players who are injured or have been injured.
"So in that respect it was a heroic physical effort, but if we want to progress in this tournament we have a lot to work on. We know that very well."
Centre-half Daniel Agger, who combined well with impressive partner Simon Kjaer, was equally ruthless in his assessment of Denmark's display.
"That was one of the worst performances we've had in a long time," said the Liverpool defender.
Denmark found themselves one down with less than ten minutes on the clock, and Olsen knows his side cannot afford to make the same start against the Japanese.
"We actually didn't start very well, we had one good chance through Rommedahl and, and just after that we made an individual mistake and they scored," he said.
"But we showed spirit, we got back in the game, we showed that we wanted to win.
"We showed things today that we don't want to do again, that's for sure, that we need to talk to the players about over the next couple of days.
"But we did have a number of chances. Compared to the game with Holland [a 2-0 defeat] there were more chances.
"We had a heroic fight in defence, but there were other problems as well. It was difficult to get the ball off the opponents and we need to improve on going forward as well."