Sam Hird gave an honest opinion of his side's performance after a series of individual errors condemned the Spireites to their second league defeat of the season on Saturday.
Shane Ferguson opened the scoring for Millwall, before a brace from Steve Morrison gave the Lions a three-goal cushion going into the second half.
Centre-back Hird scored Chesterfield’s only goal of the game to pull one back, but admitted it provided little consolation as it proved to be in vein.
“Obviously I was happy to get the goal but it means nothing when you come away losing 1-3 and you have been a part of a defence that have conceded three goals,” Hird reflected.
“I thought that we would put a bit more of a fight up after I had scored, but we didn't really put much pressure on them in terms of chances on goal.
“We put a lot of pressure on them in terms of possession and crosses into the box, but ultimately we have conceded three sloppy goals and haven't been ruthless enough in front of their goal.
“We are massively disappointed, we’re angry and we’re unhappy with ourselves, especially after the first half. You can’t really legislate for conceding goals like that - individual errors - it gave us a mountain to climb in the second half.
The 28-year-old insisted that the side will be putting in the hours on the training ground to make things right ahead of their upcoming trip to Wimbledon next Saturday, insisting that the goals they conceded don't show the whole picture.
“As footballers it is our job to work on it behind the scenes and do our best to put it right and make sure we move forwards and not backwards.
“We expected a Millwall side who would be direct and hurt us from set plays but we have dealt with all that, it is the fact that we have given away sloppy goals and you really can’t legislate for stuff like that, it is just poor.”
The trip to Wimbledon will pose its own physical problems, but Hird believes that his side combatted this well against a similarly physical Millwall side.
“We have worked on set-plays but I don't think we need to look too much into it, we have conceded two against Shrewsbury and one against Rochdale but other than that I think we are quite strong on set plays, defensively.
“As soon as you concede a goal from a set play people will say you need to work on set-plays, when you don’t score from set-plays people will say you need to work on scoring from set plays and if you concede from open play they will say you need to tighten up at the back. There are always going to be things to work on.
“As a group of players it is our job to put it right, it would be nice if we had a league game on Tuesday but it is still a match, a competitive match, and we will be looking to put it right and win.”