An injury-ravaged Chesterfield side fell to their third defeat on the trot after another dreadful display on Boxing Day.
This time the happy beneficiaries were Crewe Alexandra, who moved six points clear of the Spireites with a 2-0 victory.
Jack Lester was forced to field a makeshift backline with Ian Evatt out injured, left-back Jerome Binnom-Williams standing in alongside Sam Hird - himself carrying a knock.
And defensively Town looked very shaky in a first half that saw them concede twice.
The first came on just seven minutes, exactly the start Town didn’t need, Chris Porter breaking the offside trap and playing the ball across the area, Binnom-Williams putting it past his own keeper.
Lester’s men looked for an immediate response but Joe Rowley’s cross-cum-shot was saved by Ben Garratt.
Things then went from bad to worse.
A sliderule pass put Charlie Kirk in on the left hand side and he finished past emergency loan keeper Jake Eastwood, Binnom-Williams’ despairing slide unable to keep the ball out.
Town lost Robbie Weir on 35 minutes, the Ulsterman unable to shake off the effects of tonsillitis.
The second half at least saw a little more attacking endeavour from the hosts, but a lack of composure and the form of Garratt denied them.
The stopper was forced into action with a fine back post save when Andy Kellett whipped in a lovely cross and Rowley met it with a diving header.
Rowley was unlucky again when his shot from 20 yards was deflected wide.
Former Spireite Jordan Bowery had a chance to wrap things up 12 minutes from time when he streaked clear of the defence, but upon reaching the box he hammered well wide of goal.
Bowery had another go, this time from 12 yards, but young Eastwood came up with a decent save.
Sam Hird had to make a last ditch tackle to keep Chris Dagnall out as the Alex finished the game strongly against a very tired looking home outfit.
There was an opportunity to pull one back in stoppage time, but Dennis saw his shot palmed out by Garratt and the away side celebrated a deserved victory.
Chesterfield: Eastwood, McCourt, Binnom-Williams, Hird, Wiseman, Weir (Dimaio 35), Reed, Rowley, Kellett, Dennis, O’Grady (De Girolamo 83). Subs: Parkin, Ofoegbu, Mitchell, German, Wakefield.
Crewe Alexandra: Garrtt, Ng, Bakayogo, Raynes, Nolan, Lowery, Dagnall, Kirk (Cooper 79), Ainley (Pickering 73), Porter (Bowery 65). Subs: Richards, Walker, Reilly, Stubbs.
Referee: Mr Tom Nield. Assistants: Mr Declan Ford, Mr Gary Hilton.
Goalscorers: Own goal 7, Kirk 26
Yellows: Cooper 90
Attendance: 5,904 (338 away)