A Marc Richards hat-trick led Port Vale to their first win at Saltergate since 1989 as promotion-chasing Chesterfield were thrashed 5-0.
Robert Taylor opened the scoring before Richards took charge and a Craig Davies penalty completed the rout after Alan Goodall was red carded for bringing him down.
Vale went in front in the 19th minute when Taylor seized on a poor pass from Ian Breckin to smash in a low shot from the edge of the area.
Chesterfield should have equalised in the 41st minute but Adam Rundle missed an open goal at the back post and two minutes later, Vale increased their lead.
A free-kick dropped to Richards on the edge of the six-yard box and he hooked a shot past Tommy Lee for his 17th goal of the season.
Chesterfield had been outplayed in the first half and it got worse for the home side when Richards thumped in an unstoppable shot from the edge of the area in the 50th minute.
Vale added a fourth 10 minutes from time when Lee Collins crossed and Richards completed his hat-trick with a close range header.
Davies then converted an 85th-minute spot kick to complete a memorable afternoon for Micky Adams' side.
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