Caleb Folan's late strike secured a stunning win for Chesterfield over West Ham in the Carling Cup third round.
The Hammers defence can only watch as Folan strikes
It piles more misery on to Alan Pardew's Premiership side who have now lost eight games in a row.
Marlon Harewood opened the scoring with a fabulous volley but the Spireites never stopped battling.
Colin Larkin equalised after the interval, leaving Folan to grab the headlines for the League One side with a cool finish four minutes from time.
The Hammers had gone 672 minutes without a goal until Harewood opened the scoring in stunning fashion in the fourth minute.
Rueben Hazell's weak header from a long punt from Robert Green saw the ball fall to Harewood who volleyed home from the edge of the box.
Chesterfield fought their way back and fully deserved their equaliser nine minutes into the second half.
Folan impressed throughout and after his shot was palmed onto the woodwork by Green, Larkin poached and coolly slotted home the rebound.
Bobby Zamora had two excellent opportunities in the final 15 minutes, assisted particularly by some cute passes from the experienced Teddy Sheringham.
With the West Ham defence looking increasingly nervous, it was left for Folan to poke the ball under Green and send the home fans ecstatic.
Chesterfield: Roche, Bailey (Lowry 58), Hazell, Downes, O'Hare, Hall, Niven, Allott, Hurst, Folan, Larkin (Allison 90).
Subs Not Used: Jordan, Kovacs, Jackson.
Goals: Larkin 54, Folan 87.
West Ham: Green, Pantsil, Gabbidon, Ferdinand, McCartney (Konchesky 69), Reo-Coker, Mullins, Dailly, Reid (Etherington 57), Harewood (Sheringham 51), Zamora.
Subs Not Used: Carroll, Cole.
Goals: Harewood 4.
Ref: L Probert (Gloucestershire).