Derek Niven netted his first goal for Chesterfield to boost his side's hopes of staying up against 10-man Blackpool.
Blackpool almost went ahead when Matt Blinkhorn capitalised on a defensive blunder but saw his shot fly over.
Chesterfield took the lead when Glynn Hurst broke down the left and crossed for Niven to coolly slot home.
Blackpool keeper Phil Barnes was then sent off for bringing down Marvin Robinson but defender Steve Elliott saved Hurst's weak penalty kick.
Chesterfield: Muggleton, O'Hare, Dawson, Blatherwick, Davies,
Hudson, Niven, Innes, Brandon, Hurst, Reeves. Subs: Howson,
Richmond, De Bolla, N'Toya, Robinson.
Blackpool: Barnes, Grayson, Flynn, Elliott, Burns, Wellens,
Southern, Matias, Donnelly, Murphy, Blinkhorn. Subs: Clancy,
Bullock, McMahon, Davis, Mangan.
Referee: P Armstrong (Berkshire).