Byron Harrison's first goal for the club, which came at the end of the first half, gave the Spireites a valuable 1-0 victory at Bradford City.
There was a surprise when the teams came out for kick-off as Armand Gnanduillet, whose name was in the starting line-up on the team sheet, failed to appear. In his place was Harrison. It later emerged that Gnanduillet had suffered an injury in the warm-up. Ritchie Humphreys returned to the side in midfield with Jay O'Shea and Ollie Banks dropping down to the bench.
After a quiet opening to the game, Sam Clucas had Chesterfield's first real chance, putting a snap-shot wide.
Bradford responded with an effort from Jon Stead, who shot straight at Tommy Lee.
Clucas then swung over a low cross from the left which just evaded Harrison, who was in a good position inside the area.
In a decent spell for the hosts, Tenday Darikwa stooped to head clear at the near post from Billy Knott's dangerous corner and Stead put an effort off-target from Stephen Darby's low cross.
Chesterfield were gifted a goal in first-half stoppage time when Gary MacKenzie attempted to head the ball back to keeper Ben Williams but his header was weak, allowing Harrison to nip in and slot the ball home.
Darikwa was booked after committing a foul which resulted in a free-kick.
Christopher Routis then fired off-target from just outside the area as Bradford went in search of an equaliser.
James Hanson got a header on-target, but Lee claimed the ball comfortably under the bar.
Paul Cook made a change in the 72nd minute, taking off Harrison and replacing him with Mani Dieseruvwe.
There was a second substitution a couple of minutes later with O'Shea taking over from Roberts.
Dieseruvwe received a yellow card when he was penalised for his challenge on Rory McArdle.
Following a threatening run, Clucas fired well off-target.
Lee reacted well to keep out an effort from substitute Tony McMahon.
As the match moved into stoppage time, O'Shea had a shot deflected wide.
The Spireites held on in six minutes of added on time to secure a victory which takes them up to sixth in the table.
Chesterfield: Lee, Darikwa, Talbot, Evatt, Hird, Humphreys, Ryan, Morsy, Roberts (O'Shea 74), Clucas, Harrison (Dieseruvwe 72)
Unused substitutes: Flatt, Jones, Raglan, Banks, Ariyibi
Bradford City: Williams, Darby (Zoko 83), Meredith, McArdle, Liddle, MacKenzie (Yeates 72), Routis (McMahon 74), Knott, Clarke, Stead, Hanson
Unused substitutes: Unwin, Dolan, Webb-Foster, Mottley-Henry