Jim Mallinder blamed a lack of confidence for Saints’ below-par showing in the 27-11 defeat to Gloucester.
Northampton turned in one of their worst displays of the season so far to slip to a shocking reverse against their Premiership play-off rivals.
Two tries from Jonny May and 17 points from the boot of Rob Cook did the damage as only a Phil Dowson score and six points from Stephen Myler restored any pride.
Not for the first time, Saints failed to click in attack at Franklin’s Gardens and Mallinder feels his men are short of self-belief.
“It’s disappointing,” he said. “I think what we have got is a good squad of players but we’re playing without confidence at the moment.
“If you look at our backs, we’ve got some good players in there but they’re not functioning as well as they possibly can do.
“We as coaches and players have just got to take that on board. We accept that we’re not playing on top of our game.”
Saints’ structure was also shattered by two sin-binnings, one in either half for GJ van Velze and Samu Manoa.
Mallinder admitted that lack of discipline was unacceptable and urged his players to show more nous in pressure situations.
“If you look at it, attacking wise we were poor,” he said. “Very disappointing.
“We did have our chances - a couple of driving mauls and a good attack where we attacked the blindside - but we just couldn’t get across the try line.
“Then, on the flip side, we conceded two very soft, easy tries and to concede a try like that, direct from the lineout, then from turnover ball, is quite demoralising.
“Ill discipline as well. You can’t be going down to 14 men and we did it twice.
“It was a good try by Dowson to give us a chance but then to go back to 14 men is a killer.
“It (Manoa’s punch following Dowson’s try) was ill discipline. People are going to get wound up and they’ve got to be good enough to take it. You can’t be doing things like that.”