Alan Gaffney has labelled Saints' first-half performance against Sale Sharks 'absolutely abysmal' and 'depressing'.
The black, green and gold were 31-6 down at half-time before a second-half revival saw them beaten 34-25 at Franklin's Gardens.
Staff and supporters had worked tirelessly to ensure the game went ahead, despite sub-zero temperatures and heavy snowfall in Northampton.
But they were not rewarded on the pitch, with Saints beaten at home by Sale for the first time since May 2006.
And technical coaching consultant Gaffney was pulling no punches in his assessment of the game.
"It (the first-half performance) was absolutely abysmal - there's no other way to describe it," Gaffney said.
"We thought we had a reasonable week at training, but obviously the message hasn't sunk in with a number of players.
"We just turned too much ball over, as we have for many weeks now.
"It's very hard to work out and what we put out there in the first half was depressing.
"It will be difficult for people to hold their head up high after that first-half performance.
"We came out in the second half and played some reasonable rugby, but still didn't value the ball enough.
"We created a lot of opportunities and could have come away with more than we did, but we put ourselves in such a predicament by half-time that it was a long, hard grind."
Second-half scores from Michael Paterson, Rob Horne and Heinrich Brüssow gave the home supporters something to shout about.
But Saints took no Aviva Premiership points from the game.
And Gaffney added: "The players have got to own up.
"It's a difficult thing for them to walk in at half-time and look you in the eye.
"A lot of the players have got to examine their own performances and they will be asked to do that.
"They've got to come back and talk to us about things that happened in that half.
"Some of the decisions we took were very, very poor."