TOWN'S hopes of moving solidly into the top two were crushed by a shocking second-half performance last night.
Leading through David Graham's brilliant 13th-minute header and dominating in entertaining style, Peter Jackson's side had an automatic promotion slot for the taking as they were roared up the tunnel at the break.
That chance had been lost, and possibly for good, by the time boos rang out at the final whistle following Paul Hall's double which gave battling Chesterfield six points at Town's expense this season and mathematical safety in League I.
So dramatic was Town's demise that they failed to create a single effort on target in the second 45 minutes.
Even Andy Booth - a surprise inclusion on the bench and sent on for the final 18 minutes - couldn't poach or create a late leveller as 492 travelling fans went wild and almost 13,000 others slipped away into the moonlight.
It was a sickening blow for Town - rekindling the bitterness of that last-day defeat at Cheltenham a couple of years ago - and I can't remember Jackson looking quite so gutted since then as he did last night.
He acknowledged Town's chances of automatic promotion now rely on other clubs slipping up, while there's also concern about only a three-point advantage on seventh-placed Swansea - especially as all the leading contenders have better goal differences than the Galpharm side.
Town's three matches left are against sides in the bottom five but, if they fail to re-fit the wheels which fell off so disastrously against Wayne Allison and Co, they can forget about any easy ride into possible post-season competition.
Playing with width, pace and passion in the first half, Town seized control and looked well set for the two goals and three points needed to elbow Colchester out of second.
Graham had a handful of chances including the one he put away, which followed excellent build-up from the two Dannys, Adams and Schofield, while Chris Brandon also had a fierce drive saved and Gary Taylor-Fletcher saw keeper Barry Roche scramble to smother his goalbound shot.
The non-emergence of lively full-back Andy Holdsworth (groin injury) for the second half seemed to have a massive impact on Town, especially as replacement Tom Clarke quickly had to go off feeling ill.
Chesterfield's switch to a 4-4-2 formation also paid dividends for manager Roy McFarland, whose men exploited too much space between the over-committed midfield and over-stretched defence and grabbed themselves a comeback win.
Keeper Paul Rachubka had already made tremendous saves from Mark Allott and Jamie O'Hara when Hall equalised on 54 minutes.
O'Hara and Allison were involved in the build-up and when the former Town man crossed low into the six-yard box from the left, Hall got a lucky touch to control before forcing the ball over the line.
Thirteen minutes later and Town's nightmare got much worse.
With the defence looking in disarray and cover from midfield non-existent, Allott sent Hall past the offside trap and, from long range, he was able to curl the ball beyond Rachubka and into the unguarded net.
McFarland, who was right behind the shot, was leaping in the air and clenching his fists in celebration long before the ball crossed the line.
He knew what an important moment it was, because Town's fluency was nowhere to be seen at that stage despite the best efforts of skipper Jon Worthington and hard-working Gary Taylor-Fletcher.
Schofield and Chris Brandon disappeared from the major action in the second half while there were half chances for Booth, Schofield, Graham and Mark Hudson against his former club in the closing stages.
Graham's high volley into the Chesterfield fans, however, summed up Town's night and, having made a mess of this assignment, they face a big test to make sure they don't ruin the run-in with further sloppy goals conceded and points lost.
Man of the Match: Jon Worthington
NO-ONE showed more commitment over the 90 minutes than the skipper, who will now serve a ban for three games. He kept going even when the wheels fell off for Town 2nd half.
Next page: Turning Point and Ratings >>>
Town didn't look the same in the second half and sorely missed the strong contribution of full-back Andy Holdsworth on the righthand side.
He went off at the break suffering a groin injury and his replacement, Tom Clarke, quickly fell ill and had to come off himself. Skipper Jon Worthington ended up at No2 before his ban.
How They Rated:
Paul Rachubka Little he could do with either goal after making a fine save from Allott's drive at the start of the ill-fated second half. Rating: 6/10
Andy Holdsworth Had an excellent first half before going off suffering a groin injury. His energy and attacking flair were missed sadly by Town Rating: 6/10
Danny Adams Involved superbly in the build-up to Graham's goal and put in some thumping tackles to try and inspire the team Rating: 6/10
David Mirfin Not the good result with which he hoped to mark his 21st birthday as Town slumped badly in the second period Rating: 6/10
Nathan Clarke Handled Allison really well in the first half and stuck to his guns in the second, although Town got badly exposed Rating: 6/10
Danny Schofield Posed a massive threat first half but completely faded out of the game in the second. Made Graham's goal superbly Rating: 6/10
Jon Worthington Bags of effort on his last appearance of the regular season and he deserved better than a sickening defeat Rating: 7/10
Mark Hudson Did some bright things and showed plenty of enterprise first half, but found the going a lot tougher after the break Rating: 6/10
Chris Brandon Went through his party pieces first half and was a genuine threat. Had one cracking drive beaten out by Roche Rating: 6/10
David Graham Scored a fine seventh goal for the club in the 13th minute with a header and had other chances. Faded late on Rating: 6/10
Gary T-Fletcher Never stopped grafting despite Town's woes in the second half. His breaks in the first half were a real feature Rating: 7/10
Spotlight on the ref:
Staffordshire official Phil Dowd had a good match, although there were times when he brought play to a halt when he may possibly have let it run.
There was a stage when he seemed to whistle for every single challenge, but he stayed well on top of any potential flashpoints, having a strong word with Roy McFarland at one stage.
Chesterfield: Roche; Bailey (O'Hare 41), Kovacs, Downes, Picken; Hall (Larkin 86), Niven, Allott, O'Hara, Hurst; Allison. Subs not used: Davies, Smith, Beckwith.