Chesterfield suffered a dreadful home defeat to the National League's bottom club Chorley on a miserable afternoon in the pouring rain at the Proact.
The Lancashire part-timers, who the National League's lowest scorers and had just won once all season before this game, were 2-0 up inside 20 minutes through goals from Courtney Meppen-Walters and Charles Vernam.
Curtis Weston's superb second-half strike from the edge of the box dragged Town back into the game with 25 minutes to go, before Vernam grabbed his second from the penalty spot after he was fouled in the area by Will Evans.
Scott Boden bagged goal number eight of the season with eight minutes remaining but Chesterfield could not force an equaliser.
It was a dreadful afternoon for the Spireites who had won four of their last six and suffered only one loss in seven in the National League before kick-off.
The defeat leaves Town still in 18th, but rather than looking up the table, on this evidence, they should be looking over their shoulder as they sit just three points above the relegation zone.
John Sheridan made two changes to the team that drew 2-2 against Ebbsfleet United a fortnight ago with Weston and Tom Denton replacing Gevaro Nepomuceno, who has been on international duty, and Mike Fondop who dropped to the bench.
Josef Yarney missed out again with a slight hamstring injury while Laurence Maguire was involved in the squad for the first time since September after being out ill.
David Buchanan made his first start at the Proact since August after recovering from an ankle injury.
In the pouring rain, the visitors, who had won just one game all season going into this game, incredibly raced into a two-goal lead after 20 minutes through debutant Vernam and Meppen-Walters.
Vernam, on loan from Grimsby Town, broke the offside trap on 15 minutes and slotted past Shwan Jalal after a long ball over the top of the home defence.
Just four minutes later, Meppen-Walters powered home a header from a Martin Smith set-piece to double the lead for the part-timers from Lancashire.
Chorley continued to press and looked like adding a third when a dangerous cross flashed across the Chesterfield six-yard box.
It had been a really lacklustre half by Town, who had only threatened twice in the opening 30 minutes through Weston.
The midfielder sliced a knockdown by Tom Denton over the bar from 12 yards and then tested Chorley 'keeper Matt Urwin from around 25 yards but it was straight at him, which turned out to be Chesterfield's only shot on target in the opening 45.
The Spireites lacked confidence and ideas as Chorley, without an away win, comfortably saw out the first-half with a two-goal lead.
After the break Jonathan Smith fired high and wide from inside the box while at the other end Vernam came close to notching his second with a curling effort on the angle from the edge of the box.
Boss Sheridan made a triple sub before the hour with Maguire, Fondop and Liam Mandeville replacing Tom Denton, Robbie Weir and Buchanan.
The change almost paid off immediately when the ball fell to Fondop in the box at the far post but his shot was blocked for a corner.
With just over 20 minutes to go Chesterfield halved the deficit when Weston fired the ball into the top corner from the edge of the box for his second of the season.
Town defender Haydn Hollis almost grabbed an equaliser soon after when he glanced a Jay Sheridan free-kick towards goal but Chorley 'keeper Unwin tipped it over for a corner.
And the home side paid the price with 15 minutes to go as Vernam tucked away a penalty after pouncing on an error by Will Evans, who then brought him down in the box. He received a yellow card but it could quite easily have been red.
There was another glimmer of hope for Town as Boden scored from a yard out after Unwin parried a Fondop header straight to the striker with eight minutes remaining.
Boden almost pinched a point for Town two minutes later but he was denied by Unwin from close range.
Chesterfield: Jalal; Weir (Maguire, 59), Evans (c), Hollis, Sheridan; Buchanan (Mandeville, 59); Smith, Weston, Rowley; Denton (Fondop, 59), Boden. Subs: Coddington, Maguire, McGlashan, Mandeville, Fondop.
Chorley: Urwin, Challoner, Ross, Meppen-Waters (c), Baines, Blakeman (Cottrell, 70), Smith, Nortey, Newby (O'Keefe, 75), Carver, Vernam. Subs: Cottrell, Dodds, Newby, Massanka, O'Keefe.
Referee: Karl Evans