Dave Jones said his players lacked discipline, hunger and professionalism in Tuesday's 2-0 away defeat to Ipswich Town.
"Some of the players didn't go out with the attitude that they needed to work hard. And that's the frustrating thing because they're good players," he said.
"But good players have to work at their game, work to get into the game when things aren't happening.
"I felt too many of them weren't prepared to do that."
"The two goals are a joke because they are two goals we can stop," fumed Jones.
"I can set that up in training every day of the week and we wouldn't get caught. That's switching off and that's not acceptable."
It was in stark contrast to the battling victory over Middlesbrough on Saturday.
"What's changed? Maybe it's down to a discipline of attitude," added Jones.
"In games like this you've got to work your way into. Individually you've got to work really hard and if things aren't working out for you then you've got to work at it.
"Keep running, keep trying to get your tackles in, keep trying to make the opposition make a mistake. But certain players didn't do that and that's the annoying thing.
"We did it on Saturday and maybe they thought it was just going to happen again."
Town boss Roy Keane was pleased to see Daryl Murphy continue his recent run of goals after his loan move from Sunderland.
"I spoke to him in the summer about joining and he probably regrets that that didn't happen," Keane said
"He's come in and had a run of games and his biggest strength is definitely playing through the middle.
"He's getting chances in every game and I was pleased with his goals tonight.
"They were poacher's goals, particularly the second one.
"We haven't scored anywhere near enough like that this season and need more.
"We try to score so many wonder goals after 15 or 16 passes."
Keane was satisfied with his side's performance and pleased to climb up two places to 17th.
"We scored two, their keeper made two particularly good saves and I thought we played not bad," said the Irishman.
"We kept it well, stretched them when we had to, created chances and the players looked like they enjoyed it.
"In terms of keeping the ball, our tackling and our shape, the tempo was decent."
