A remarkable second half showing saw the Spireites turn a half time defeicit into a 4-2 Port Vale win to live long in the memory as the hosts won in their survival struggle.
After sustained Vale pressure, AJ Leitch-Smith opened the scoring ten minute before half time after a neat turn, a goal equalised by Jamal Campbell-Ryce moments into the second half from similar range.
Sam Hird turned the game on its head with a slamming header on the hour before Vale substitute JJ Hooper levelled things again ten minutes later.
However, the Spireites quickly regained their lead with a Gboly Ariyibi close-range effort before Jay O'Shea popped a cherry on the cake a a well-taken 25-yard volley.
Connor Dimaio returned to the starting line-up after being on international duty with Rai Simons and Ollie Banks also handed recalls. Ariyibi, Liam O’Neil and Sylan Ebanks-Blake were the ones to make way.
The Spireites survived a scare in only the third minute when Drew Talbot made an important block as the visitors threatened to break through.
As Vale continued to make the early running, Sam Foley volleyed well off-target.
Chesterfield’s first opening was carved out following a link-up between Dimaio and Simons, with the former putting a low shot wide.
Charlie Raglan, playing against his old club, then had a half-chance, seeing his shot trickle wide of Jak Alnwick’s right-hand post.
Vale posed another threat when Ben Purkiss slipped the ball through to Foley who missed the target with a low, angled shot.
Just after the half-hour mark, Vale’s Anthony Grant received a yellow card after a heavy challenge on Simons as the Bermuda international looked for an opening.
The visitors created another good opening when Louis Dodds found some space on the right-hand side of the area and played the ball across the face of goal, but it just evaded Leitch-Smith.
In their next attack, Vale opened the scoring when Leitch-Smith took advantage of some uncertain defending, stabbing the ball into the corner of the net.
Just before the break, Lee Novak tried a shot from distance which was deflected off-target.
Manager Danny Wilson made a double substitution at the resumption of play, sending on Gboly Ariyibi and Jay O’Shea in place of Dimaio and Simons.
Ariyibi made an immediate impact, with his low cross picking out Campbell-Ryce (47) who calmly picked his spot before placing the ball expertly past Alnwick.
Raglan was in the thick of the action, having a goal-bound shot blocked and then heading wide.
Buoyed by the goal, the Spireites were playing with new-found confidence and Campbell-Ryce tried a curling effort that drifted beyond the far post.
Chesterfield took a 60th minute lead when O’Shea’s free-kick from the right was met by a Hird header, to the delight of the home fans.
Carl Dickinson was a fraction away from equalising shortly afterwards when his deflected shot came back off the bar.
There was no similar let-off when Chesterfield were caught on the break and substitute Hooper (70) burst into the area before firing past Tommy Lee.
Just three minutes later, the Spireites regained the lead when Vale failed to clear following O’Shea’s corner and Ariyibi found the net from close range.
Novak went close with a shot which took a deflection wide before O’Shea (83) added a fourth, scoring with a shot from the edge of the ‘D’ after being found by Ariyibi.
Chesterfield: Lee (gk) - Talbot, Anderson, Raglan, Hird - Dimao (Ariyibi 46'), Liddle (c), Banks, Campbell-Ryce (Orrell 90'), Simons (O'Shea 46') - Novak
Subs not used: Herd, Humphreys, Chapman (gk), Slew
Port Vale: Alnwick (gk), Purkiss, Streete, Duffy, Dickinson (c), Moore (Kennedy 75'), Foley (Brown 81'), Grant, Kelly, Dodds, Leitch-Smith (Hooper 57')
Subs not used: Boot, McGivern, Birchall, Robinson
Chesterfield: Campbell-Ryce 47', Hird 60', Ariyibi 73', O'Shea 83'
Port Vale: Leitch-Smith 36', Hooper 70'
Attendance: 5,917 (485 away fans)