The Spireites slipped to a 2-0 Carabao Cup defeat to local rivals Mansfield Town on Tuesday evening.
Goals from Rhys Oates and Will Evans meant that Chesterfield exited the competition at the first round stage.
Paul Cook made three changes from the side that beat Cheltenham on Saturday, with Matt Dibley-Dias and Ronan Darcy getting their first starts of the season, and Will Grigg back leading the line from the off.
This hotly anticipated fixture did not take long to come to life, and after just two minutes, the visitors took the lead.
In what was Mansfield’s first foray into the Chesterfield half, Oates latched on to a through ball and finished low past Zach Hemming.
The Spireites, buoyed by the raucous sell-out home crowd, continued to press after the goal, with several attempts requiring intervention from Mansfield’s Liam Roberts.
Darcy looked set to get the equaliser shortly after, but his deflected attempt rolled agonisingly past a post.
Again, Roberts was forced into a smart stop, this time from Dobra, whose driven effort looked destined for the bottom corner.
In what was becoming a theme of the half, Roberts thwarted both Chey Dunkley and Dobra as the Spireites launched wave after wave of dangerous attacks.
With ten minutes left of the half, Darcy had another opportunity for Town, but a combination of Roberts and Bailey Cargill was enough to keep his effort out.
It was a tentative start to the second period from both sides until the 59th minute when Mansfield doubled their advantage.
Evans latched onto a wayward pass from Dunkley, and his strike was too strong for Hemming.
After their second goal, the League One outfit began to stifle any threats from the Blues.
Hemming was forced into a full-stretch save 15 minutes from time when tipping Aaron Lewis’ free-kick over the bar.
The Spireites were adamant that they should have had a penalty in the 80th minute when Dylan Duffy was impeded in the area, but the referee waved away the protests.
Mansfield ultimately managed to see the tie out.
Attention now turns to Saturday’s league game at home to Bristol Rovers (12.30pm).
Chesterfield: Hemming, Daley-Campbell, McFazden, Dunkley, Gordon, Stirk, Darcy (Mandeville 76), Dibley-Dias (Naylor 39), Dobra (Duffy 68), Markanday (Butterfield 76), Grigg (Bonis 68)
Attendance: 9,502
