A pair of half-time substitutions inspired Chesterfield to a magnificent comeback and three vital points.
The Spireites left the pitch 1-0 down to Port Vale at the break, amid a chorus of boos, having failed to register a shot on target in an inspid display.
But what followed the interval was in stark contrast, substitutes Gboly Ariyibi and Jay O’Shea turning on the style to bag a goal and an assist each in the 4-2 win.
Jamal Campbell-Ryce and Sam Hird also capped fine displays by getting on the scoresheet, as the visitors saw their play-off hopes further dented.
The Proact erupted in relief and appreciation at full-time, that first half mercifully erased from memory.
Port Vale looked dangerous early on, and their hosts looked decidedly nervy.
A vital Drew Talbot block kept out a goalbound effort from Louis Dodds as early as the third minute.
Connor Dimaio, celebrating his new two-year deal at the Proact, had the hosts’ first chance, linking up with Rai Simons and then trundling his shot past the right hand upright.
The visitors got to grips with the game and had periods of sustained pressure in the first half an hour, but created little more than a chance for Sam Foley, who received the ball in the box and fired past the far post.
There was a big let off for the hosts when Dodds got free of his marker and fired the ball right across the face of goal, the cross-cum-shot somehow missing at the far post.
But two minutes later there was no reprieve, a ball into the six-yard-box that could have been cleared twice eventually finding AJ Leitch-Smith who turned and slotted home.
The half-time whistle was greeted by boos from the home supporters, Chesterfield marking 225 minutes of football with no shots on target.
Wilson went for a double change at the break, taking Dimaio and Simons off and sending on Jay O’Shea and Gboly Ariyibi.
Chesterfield benefitted almost immediately, Ariyibi sprinting down the left and curling in a cross that fell to Campbell-Ryce, who blasted in an equaliser.
With their tails up, they looked a new side, Raglan seeing a volley cleared off the line and a header just miss.
The game turned entirely on its head on the hour mark, O’Shea’s deep free-kick nodded into the net by Hird, sparking wild celebrations.
Vale stemmed the tide, temporarily, Carl Dickinson’s deflected cross hitting the bar two minutes before JJ Hooper took a lovely through ball and curled in a fine finish to level.
Chesterfield went straight back on the attack however, Campbell-Ryce and O’Shea winning a corner that the latter sent into the box where Ariyibi swivelled and found the net.
The win was sealed 18 minutes from time by Man of the Match O’Shea, who slammed home a 25-yard half volley that beat a bealeagured Alnwick to his right.
Chesterfield: Lee, Hird, Talbot, Raglan, Anderson, Liddle, Dimaio (Ariyibi 46), Banks , Campbell-Ryce (Orrell 89), Simons (O’Shea 46), Novak. Not used: Herd, Humphreys, Chapman, Slew.
Port Vale: Alnwick, Purkiss, Dickinson, Streete, Duffy, Dodds, Foley (Brown 81), Kelly, Moore 6 (Kennedy 75), Leitch-Smith 7 (Hooper 57), Grant. Not used: McGivern, Birchall, Hooper, Boot, Robinson.
Goalscorers: Campbell-Ryce 47, Hird 60, Ariyibi 72; Leitch-Smith 36, Hooper 71
Yellows: Campbell-Ryce 47; Grant 31, Duffy 59, Purkiss 68
Referee: Kevin Wright. Assistants: Marvyn Amphlett, Karl Evans.
Attendance: 5,917 (485)